The M17 series of protective masks were a series of field protective masks standardized for the United States military in March 1959 and used through the middle 1990s when it was officially phased out with the introduction of the new M40 series protective mask.
- 1 Background
- 2 Prototypes
- 3 ABC-M17
- 4 M17A1
- 5 M17A2
- 6 Manufacturers and Rubber Markings
- 7 Filter Elements
- 8 Maintenance Issues
- 9 Accessories
- 9.1 M1 Water Canteen Cap
- 9.2 M4 Winterization Kit
- 9.3 M1 Resuscitation Hose
- 9.4 ABC-M6A2 Field Protective Mask Hood
- 9.5 Neutral Gray Eyelenses Outserts
- 9.6 Green Laser Protection Eyelenses Outserts
- 9.7 Brown Laser Protection Inserts
- 9.8 Optical Inserts
- 9.9 M13 Individual Decontaminating And Re-Impregnating Kit
- 9.10 M258 Series Personal Decontamination Kit
- 9.11 M8 Chemical Agent Detector Paper
- 9.12 M1A1 Waterproof Bag
- 9.13 Mark I Nerve Agent Antidote Kit (NAAK)
- 9.14 M17 Mask Carrier
- 10 Cultural Impact
- 11 Foreign Copies
- 12 Gallery
- 13 References
After WWII, and with the cold war between the US and the USSR looming, it was clear to war planners that any future war would quickly escalate from conventional to chemical and biological war. With the proliferation of the G-series and relatively new V-series nerve agents, the US military decided to design a new mask to meet the challenges of these new threats. The M9 was too bulky with the unsatisfactory large canister mounted on the side. Also being obsolete to be effective on the modern battlefield (although M9 series masks would be used for special purposes well through the mid-1990s). New design requirements were drawn up for a compact design that did not have external filter canisters or hose-connected filter elements. The internal filter pouch solution was selected to meet this form factor and also eliminated the requirement to have different designs for the left and right-handed service members. A voice diaphragm was also a design requirement to aid in battlefield speech communications in a contaminated environment. After about a decade of testing and development, a mask began production in 1959 as the ABC-M17 (Atomic, Biological, Chemical) with the same standard of protection as the M9 series, although with a longer 24 hour filtering capacity and shooter friendly design. Approximately 3.3 million M17A1 and M17A2 masks were produced between 1967 and 1986.
In the 1950s, the U.S. Army experimented with a variety of masks testing various filter technologies; many concepts that were tested were ultimately dropped. The E13-series masks tested these various configurations. The E13R4 mask had integral cheek-mounted filters and was considered superior since the mask did not require a separate filter connected by a hose and accommodated left and right-handed soldiers without modification. The final mask, adopted as the M17, was a slightly modified E13R9. Experimentation with the design continued throughout the operational life of the mask. One such variant was the XM27 created in 1966. This experimental design was basically an M17 made entirely of grayish-green silicone rubber instead of the black butyl/natural rubber formulation of the basic M17 model. While more comfortable for the wearer, the design was rejected since there was the concern of penetration of liquid persistent chemical warfare agents such as VX. A few examples of this mask were made with clear silicone rubber. It is hypothesized that these were made to illustrate the internal workings of the mask to decision makers and were not intended to be a production model. This prototype was scrapped and the XM27 is considered by collectors, especially the masks made of clear silicone rubber, as some of the rarest gas masks known to exist.
Standardized in March 1959 and seeing full scale production by 1961, the US Army issued service members the ABC-M17 protective masks for the first time. The ABC in the nomenclature was an initialism for Atomic Biological Chemical. The mask received generally positive reviews but some service members complained about the difficulty of filter changing. This first version of the M17 did not incorporate a drinking tube or resuscitation system, instead only featuring a voice diaphragm. Although the voice diaphragm was a welcomed addition to American protective masks, it was minimally compatible with radio handsets of the era. Talking on a radio while masked meant juggling the handset between ear and voice diaphragm leading to confused and muffled communications. This arrangement plagued all M17 designs and was only improved with the M40 series protective mask that has a voice diaphragm located specifically to interface with radio handsets. As newer models of the M17 were introduced, the old ABC-M17s migrated to law enforcement agencies where the advanced features of later models were not as important for simple crowd control with tear gases.
Eight years after the introduction of the ABC-M17, the US Army updated the mask design. In 1966, the U.S. Army standardized the E13R13 as the M17A1 protective mask, officially dropping the ABC prefix from the name of the mask. The new mask came new features; the addition of the drinking system and the addition of the resuscitation system.
The M1 (E49) drinking system designed for the M17A1 is believed to be the first in the world, followed shortly thereafter by British and German designs. The drinking system, standard on US protective masks today, incorporates a hose pre-attached to the mask, instead of unscrewing and screwing multiple connections together (all the while exposing the water and human body to possible contamination). The M17A1 incorporates a quick couple connector that greatly reduces the risk of contamination when used with the compatible M1 Water Canteen Cap.
The other unique feature of the mask was much less successful. The M1 (E50) resuscitation tube was incorporated with the mask that was designed to allow a masked soldier to provide artificial respiration to an unmasked casualty. The concept and execution were problematic as the use of the tube could expose the wearer to contamination. The soldier giving aid ran the risk of encountering resistance from the airway of the casualty, pushing air back into his mask and breaking its seal. Due to this problem, the resuscitation system was dropped with the design of the M17A2.
During the early 1980s, while the US government began fielding the latest XM30 and XM40 series protective masks. A stopgap would be standardized as the final variation of the M17 mask; the M17A2 protective mask. This version of the M17 mask would not feature the M1 resuscitation tube of the M17A1 and would be used by US forces deployed around the world. A variety of items, depending upon the mission, were issued with the mask and stored in the mask carrier such as a waterproof bag that would protect the mask's filters from water damage during immersion. The M17A2 also has the exterior tilt (rotary) lever for the drinking tube. The purpose of this tilt lever was to allow the user to position the inner drinking tube into one's mouth from the exterior of the mask. Once the user was done drinking, the lever would be manually tilted back and the tube would move up and away from the user's mouth. The M17A2 would use common M17 accessories such as neutral gray outserts and the characteristic olive drab NBC hood.
Although the M17A2 was phased out and replaced by the M40 series protective masks, the extra-small version of the M17A2 was retained and issued to servicemembers with particularly small faces that could not be properly fitted with an M40 series mask. The extra-small masks were issued on a case-by-case basis directly from Rock Island Arsenal and the service member would retain that mask throughout his or her career. This purpose for the extra-small M17A2 was eventually phased out when the extra small M45 was fielded as part of the Land Warrior program.
Manufacturers and Rubber Markings
MSA (Mine Safety Appliances) was the first and main contractor for the M17 series masks. It had contracted to produce face blanks since the early prototype phases of the M17 series through the end of the M17 manufacturing life. Because of this, MSA is the most common manufacturer of face blanks with most ABC-M17s and all M17A1/A2s being produced by them. Manufacturer stamps on the M17A2 can be found in two locations, one is near the right eyepiece with the manufacturer's name and year of manufacture and the second (almost hidden) mark is on the right side of the inner end of the nose cup assembly facing the internal filter compartment. Other markings include "M# C#" (e.g. M5C1) just on the top of the right or left side.
D.T was contracted to produce ABC-M17 face blanks starting in May 1960. They shared production with MSA and Firestone. They had ended their contract by 1964 leaving MSA as the only remaining manufacturer of face blanks. Because of this, D.T marked face blanks are the second rarest.
Firestone Tire & Rubber was contracted by the United States government to produce ABC-M17 face blanks starting in the third week of January, 1962 although by early 1963 Firestone's contract had ended. Due of this short production run, Firestone face blanks are the rarest with only a year of production.
The M17 series protective mask took a slightly curved, triangular filter elements often referred to as "pork-chop-shaped." The filter elements came in white airtight, vacuum-packed paper/foil laminated bags with labels indicating the filter nomenclature. The filter elements were designated M13 and were improved over time to the M13A1 and M13A2. The different generations of filter elements can be identified by the color of the connector ring:
|Filter Element||Connector Ring Color|
|M13A1||Black or Gold|
All generations of the filter elements were intended for full combat use and were effective against all known chemical warfare agents, however as each generation was introduced, the previous generation was designated as only sufficient for training with tear gas (CS) or another confidence source such as isoamyl acetate (banana oil) or camphor. The filters were not designed to filter out vapors generated from fuel, paints or solvents and the exposure to these hazardous materials would deteriorate the filter's ability to filter out chemical warfare agents. The filters could filter out radioactive particles to keep those particles out of the wearer's respiratory system but concentrated those particles in the filter media close to the face. This could pose a danger to the wearer if gamma-emitting particles are trapped in the filter media or could expose the operator to beta or alpha-emitting particles during filter changes. The filters elements were annotated with the position (left or right), lot number, and breathing resistance measured in mm of water. The left and right filter elements had to have a breathing resistance of plus or minus 5 mm of water to be considered a matched pair. An unmatched pair would lead to premature exhaustion of one of the filter elements.
Composition and Filtering Strategy
The filter elements were composed of lightweight gas-aerosol filter material that fit into cheek pouches of the mask. The filter media contained ASC Whetlerite activated charcoal that contained chromium VI (hexavalent chromium) specifically added to defeat hydrogen cyanide (AC) and cyanogen chloride (CK), both blood agents. The chromium VI additives are a known carcinogen, but the filters are considered safe for use as long as the filters are in good repair. However, the filters should be treated as hazardous waste when disposed of due to the chromium VI content. The M13 series filter elements were of a unique airflow design. The particulate filtration stage is typically located upstream of the vapor filtration stage so that volatile material released by the trapped aerosol is removed by the vapor filter. The M13 filter element pair used with the M17 protective mask is an exception to this orientation. This filter provides single-stage filtration through application of a composite material consisting of fine particle size impregnated activated carbon (for vapor filtration) mixed with glass and polymer fibers (for aerosol filtration). A disadvantage of this single-stage approach is that the aerosol can penetrate a significant distance into the composite aerosol/vapor filter material before being removed from the airstream leading to a shorter duration until the chemical agent breaks through the filter and enters the wearers respiratory system.
Changing Filter Elements
The filter elements could only be changed in a clean environment from the inside of the mask. The filter elements were notoriously difficult to change, often taking 15 to 20 minutes to complete the task. However, a well trained soldier could accomplish the task in as few as five minutes. It is worth noting that the task (task number 031-503-1010, Replace Filters in Your M17-Series Protective Mask) had no time limit.
Inlet Filter Valve Assembly
The filters were secured to the face blank on the outside with caps that contained the inlet filter valves. The inlet filter valve assembly featured a white stamp that indicated "TOP" on the outside edge of the assembly. This was to ensure the internal louvers of the assembly faced downward to shed water and presumably liquid chemical warfare agents away from the filter media. The white "TOP" stamp was often worn away or mis-stamped on the inlet valve assembly. This was corrected at the unit level with a dot of white paint where the stamp should be. The inlet valve assembly snapped onto the connector ring of the filter.
The filter elements for the M17 series mask are not compatible with the filter elements of the many foreign clones of the mask due to small differences in the size, shape and connecting mechanism. Likewise, the M13 series filter elements will not fit into any of the M17 series clones.
Although the M17 series protective masks earned a reputation as being a reliable and robust mask that could stand up to difficult field environments, the series was vulnerable to faults unique to the design.
The innovative drinking system of the M17A1 and M17A2 operated with a small lever on the outlet valve assembly. That lever became a source of maintenance problems due to service members over-torquing the lever and cracking the metal of the voice diaphragm and outlet valve assembly. It was believed that the drink tube was missing or poorly adjusted in the affected masks causing service members to over-torque the lever in frustration. The 1987 version of the technical manual addressed this problem by adding that fault to the inspection regime for the mask.
The natural and butyl rubber formulation of the M17 series mask was vulnerable to a "permanent set." That is when the rubber of the mask retains a memory of a position when stored in that position for a long period of time. For example, when the mask is stored folded in the mask carrier for an extended period of time. This condition may result in a compromised seal which rendered the mask unusable.
The black lacquered brass hardware of the C8R1 head harness system of the mask often became scratched and worn with normal training and use of the mask. This allowed copper ions to migrate into the rubber around the hardware of the mask making the rubber weak and brittle. This "copper poisoning" of the rubber was easily prevented by making sure the black lacquer on the brass hardware was in good repair and scratches or worn spots were covered with fresh black lacquer.
The filter element pouches on the mask were closed with a series of plastic dumbbell-shaped buttons and buttonholes in the rubber of the face blank and nose cup assemblies. A common fault of the mask was the tearing of these buttonholes--often due to the frustration of the service member while trying to replace the filter elements. These button closures were critical to the proper airflow through the mask and torn buttonholes were considered a deadlining fault. The task of changing the filter elements could be made easier by lubricating the plastic lugs with water or more commonly, saliva before attempting to button the closure flaps.
Eye Lens Yellowing
The polycarbonate formulation of both the eye lenses and eye lens outserts were prone to yellow over time due to exposure to UV light, excessive heat and atmospheric pollutants such as ozone. With normal use, this process is slow enough not to affect the mask during its operational life, however, masks on the secondary market and "new-old-stock" eye lens outserts can show significant yellowing. The yellowing is uniform across the lens and is sometimes mistaken for purposely colored lenses, however, no yellow-colored eye lenses or outserts were made for the M17 series mask. The final stage of the polycarbonate eye lens degradation is severe yellowing, crazing, and embrittlement of the lens material.
The butyl and natural rubber formulation of the M17 series mask has a tendency to accumulate a white, chalky
substance on its surface especially when stored without use for long periods of time. With use and maintenance, the bloom is normally worn away or washed off. Although unsightly, the bloom does not indicate damage to the function of the mask. The rubber formulation is engineered with protective substances that migrate to the surface of the mask to protect the rubber from attack by UV light or chemicals found in common decontamination solutions. The bloom may be simply washed off with mild soap and warm water.
M1 Water Canteen Cap
This canteen cap has a special fitting that allowed a service member to drink water from a standard one or two-quart canteen safely in a contaminated environment. The cap connects with the drink tube connector on the M17A1, M17A2 and subsequent US protective mask models such as the M40 series, however, the M50 series opted for a different canteen connector type that is not compatible with the M1 cap. The cap did not work with the older style canteens when introduced due to a threading mismatch but worked with all modern U.S. Army one-quart and two-quart canteens. The cap had a protective cover attached with a strap of plastic, but the plastic was susceptible to fatigue and quickly broke, losing the protective cover and rendering the cap unserviceable. Later designs incorporated a two-part strain relief system that had greater success at retaining the protective cover.
M4 Winterization Kit
This kit was an olive drab canvas cover that goes over the inlet valves. It was designed to protect the valve disks from freezing in environments below freezing, usually at below 20 degrees Fahrenheit (-30 Celsius). The kit also prevents frost accumulation on the inlet valve caps. The use of the kit increases the breathing resistance for the wearer of the mask.
M1 Resuscitation Hose
This apparatus was made specifically for the M17A1 and attached over the exhale valve allowing a masked soldier to perform mouth-to-mouth resuscitation on an unmasked soldier. The hose assembly was difficult to use and often broke the seal on the wearer exposing the service member to chemical warfare agents.
ABC-M6A2 Field Protective Mask Hood
This was the standard Nuclear, Biological Chemical (NBC) hood for the M17 series protective mask. The hood attaches to the M17 series mask and protects the wearer's head and neck from chemical agent vapors or liquid droplets, biting insects, and radioactive dust particles. The hood had a plastic fastener for the neck strap similar to the M4 hood for the M9A1 mask. The M6A2 was an updated variant; the difference being that the A2 had a different fastener type for the neck strap and a zipper that made the mask and hood combination easier to don and doff. The hood could be worn in one of two configurations; summer and winter. The summer configuration had the hood pulled up over the outlet valve forcing clean, filtered air under the hood. This theoretically overpressurized the hood to make the infiltration of chemical warfare agent vapors less likely. However, in reality, the moisture content of the exhaled air condensed on the inside of the hood and eventually saturated the chemical protective overgarment rendering the garment less effective and increased the heat load on the wearer. The winter configuration had the hood under the outlet valve allowing the exhaled air to escape to the atmosphere. This prevented the build-up of ice from the moisture-laden, exhaled air under the hood in freezing temperatures.
Neutral Gray Eyelenses Outserts
For use in high illumination areas and were essentially sunglasses for the protective mask. The outserts were not a basic issue item supplied with the mask and had to be ordered separately when missions in sunny areas were anticipated. The lenses attenuated the light but did not change the color of the light since the accurate color vision was required to read the M256A2 chemical agent detector kit tickets.
Green Laser Protection Eyelenses Outserts
For use at night or in low light conditions. These outserts provide protection from ruby and neodymium type lasers. They are made of polycarbonate and offer ballistic and impact protection.
Brown Laser Protection Inserts
These inserts were used for day use only. The inserts offer protection against ruby, neodymium, and double neodymium lasers. The inserts snap into place behind the mask's lenses. Because of this, the inserts do not offer ballistic protection.
For service members that require corrective lenses, two types of optical inserts were developed for the M17 series mask. The first consisted of a wire frame that fit into the perimeter of the eye lenses and suspended the corrective lenses roughly at eye level inside the mask. The second type attached to the area where the eye lenses met the face blank with a set of prongs. The prong type was only available with the M17A1 and M17A2 versions of the mask. The frame type optical inserts were considered safer since that type was more difficult to dislodge during the donning procedure.
M13 Individual Decontaminating And Re-Impregnating Kit
This individual decontamination kit contains a small pad and diatomaceous earth powder for decontaminating skin. The powder had a small ampule filled with a substance that changed color when in contact with chemical agents. The ampule was broken and massaged into the powder to help identify heavily contaminated areas of clothing. The kit also contained larger bags containing calcium hypochlorite powder for decontaminating clothing and equipment or for re-impregnating clothing. A cutter (packaged with a small pad) was included for cutting out liquid contamination spots from clothing.
M258 Series Personal Decontamination Kit
This individual decontamination kit replaced the M13 series kits first with the M258 and subsequently, the M258A1 kits. The M258 kit was introduced in 1975 and consisted of two bottles of decontamination solution with towelettes. The solutions were designed to neutralize both nerve and blister agents on the skin, but in an emergency, could be used to decontaminate individual equipment. The M258A1 improved on the design of the kit by incorporating the decontamination solutions in individually sealed packets. The kit contains six foil-packaged decontamination towelettes/wipes in an olive-drab plastic case that fits in a pouch in the rear of the M-17 mask carrier. Each wipe was labeled as either "1" or "2." To decontaminate your skin, you would crush the glass ampules of the packet and fold the wipe to distribute the decontamination solution. Next, open the towelette and wipe away from the body for one minute with packet number one followed by two minutes with packet number two. The broken glass of the ampules was contained in a nylon pouch that was discarded when the wipe was extracted from the foil package. Training M258 kits were available that substituted isopropyl alcohol in the packets instead of the actual decontamination solution. The training kits were identifiable by the black plastic shell of the carrier and blue colored packets. The actual combat kit had an olive drab plastic carrier and olive drab colored packets.
M8 Chemical Agent Detector Paper
Consists of a book of perforated sheets of chemically treated, dye-impregnated paper. A color comparison bar chart is printed inside the front cover. Chemicals in the paper cause-specific color changes when paper contacts liquid nerve or blister agents. The booklet consisted of 25 sheets of detector paper but each sheet was bifurcated so it allowed up to 50 tests for a liquid agent.
M1A1 Waterproof Bag
The M1A1 waterproof bag was a heavy-duty vinyl bag supplied with rubber bands that were designed to accommodate the M17 series mask with attached hood. The bag was used in operations where the mask was likely to get wet; e.g. river crossing operations. The bag was stored folded in a pouch inside the main compartment of the mask carrier. Keeping the mask dry was critical to the correct operation of the mask. If the filter elements become saturated with water, the breathing resistance would dramatically increase and the protective qualities of the filter elements would be compromised. The waterproof bag contained a high concentration of plasticizers as part of its formulation to keep the bag soft and pliable in both hot and cold conditions and after long-term storage. These plasticizers would polymerize with the rubber formulation of the mask if left in the bag for long periods of time so instructions on the bag warned to use the bag only when needed. Additionally, the instructions warned that the bag was not to be used for the storage of food or water.
Mark I Nerve Agent Antidote Kit (NAAK)
The NAAK was issued when there was a likelihood of a nerve agent attack. Three kits were normally carried in a pouch inside the main compartment of the mask carrier along with the waterproof bag.
M17 Mask Carrier
The mask carrier for the M17 series mask was a heavy cotton canvass, olive drab colored bag with nylon webbing and
brass fasteners. Later versions of the mask carrier were made from water-resistant nylon material. The mask carrier had nylon stiffeners sewn into the sides of the pouch to add to the structural integrity of the bag. The carrier had a large pouch that would contain the mask with a small pouch inside the main compartment designed to accommodate three Nerve Agent Antidote Kits (NAAK) and the waterproof bag. The carrier also had a small snapped pouch on the rear to accommodate the M13 and later the M258 personal decontamination kits. The carrier was always worn on the left side of the body in the hip or shoulder carrying configurations. The mask was stored in the carrier with eye lenses facing the opening of the carrier and the hood stored inside out to facilitate the rapid donning of the mask. The carrier had the nomenclature of the mask and often the Chemical Corps insignia stenciled on the side of the carrier.
Due to the long service life of the M17 series masks, the distinctive image of that mask diffused into popular culture, arts, and entertainment.
The ABC-M17 was the standard-issue protective mask for the United States Army throughout the Vietnam war. Although there was little risk of the use of lethal chemical warfare agents by either side, the American Army made extensive use of riot control agents (most commonly, CS) during certain missions. One of those missions was the clearing of tunnel networks dug by enemy forces to protect their forces from observation and attack with aircraft delivered munitions or artillery. The tunnel networks were filled with riot control agents through CS grenades or micro pulverized CS agent dispersers. Specially outfitted Soldiers would then clear the tunnels of enemies and booby traps. The residual CS inside the tunnels required the use of the ABC-M17 mask to be able to complete the mission. These Soldiers were nicknamed "Tunnel Rats" and captured the imagination of the public. Although the ABC-M17 was associated with tunnel rats, the less bulky and more comfortable M28 riot control mask, nicknamed the "Grasshopper Mask", took over that role in 1968.
The First Gulf War AKA Desert Storm
In 1990-1991 Gulf War brought a threat of the first large-scale chemical war since World War I to the United States and its coalition allies. Iraq was known to have a large inventory of chemical munitions and it was feared that they would be used in the effort to drive Iraqi forces from Kuwait. The United States Army made a concerted effort to show Soldiers and other coalition members donning protective gear, to include the M17A2 protective mask, to show that coalition forces were prepared for any type of chemical warfare. The U.S. doctrine at that time allowed for the use of chemical weapons in a retaliatory capacity (this was before the 1997 Chemical Warfare Convention), however, coded diplomatic language made it clear that the use of chemical weapons by the Iraqis may trigger the use of nuclear weapons by the United States. Photos of troops wearing the M17A2 mask were run in newspapers and magazines and is closely identified with that war.
Gas Mask Mooks
In the 1990s as the M17 series mask was gradually being replaced by the M40
series mask, M17 series masks began to flood the secondary market. This made the M17 a cheap and available prop for television and movie producers where the script called for faceless minions often representing a corrupt government executing malevolent plans. Notably, the X-files television series often depicts government goons of a secret and corrupt conspiracy wearing variants of the M17. The gas mask mook trope has often been criticized on logical grounds. Why would a goon need a gas mask when it is clear that there is no respiratory threat and wearing one would hamper physical performance? Clearly, the wearing of a protective mask is meant to indicate the inhumanity and lack of empathy for those wearing the masks. Even in the more accurate representations of the use of M17 series protective mask, the wearers are seen as harbingers of evil. In the 1995 movie Outbreak, Soldiers in full protective ensemble escort disease victims to collection areas to die and eventually be incinerated. Curiously, the M17 series is not well represented in video games perhaps due to the mask being out of service when sophisticated first-person shooter games were being developed. A notable exception is 2012, DayZ Standalone game where the Czechoslovakian M10M, an M17 clone, features prominently. The M17 has appeared in some post-apocalyptic art and comics throughout the 1970s and 1980s. It is assumed that the air is contaminated with chemical, biological or radiological agents in the post-apocalypse.
The M17 series mask design was copied in at least four countries. These include:
Main article: M10
Similar to the ABC-M17 but made of a light grey rubber and a different outlet valve cover assembly. Its inlet filter valve covers are threaded as opposed to the "snap-on" version of the original M17 series mask.
Main article: M10M
Identical to the M10 but includes a drinking system similar to the M17A1 and M17A2. The diaphragm and outlet valve assembly on this model are also completely made out of grey plastic as opposed to the rubber that covers the assembly on the M10 Model.
Main article: PDE-1
Same as the M10 but made of black rubber and featuring a rubber, five-point head harness.
Main article: MP-4
A direct clone of the M17. Older models were made of an olive-colored rubber with olive drab straps while newer models are made of gray rubber with blue straps. The eye lenses on the MP-4 are slightly farther apart when compared to the original M17.
Korean Samgong made M17 in the 70s-80s.
Type 3 (Japan)
Main article: Type 3
It is one of the closest copy, only the rubber colour is different, which is green.
- Edgewood Chemical Biological Center 85th Anniversary Flyer 
- The History of Military Mask Filters
- XM 27 Article
- Facebook Post.
- SB-3-30-2 Chemical - Biological Canisters and Filter Elements: Serviceability Lists Manual
- Field Manual 3-8, Chemical Reference Handbook, Page 64
-  TM 3-4240-279-10 (M-17A2 User Technical Manual)
- ECBC-TR-135 NBC Filter Performance Dated October 2001
- Talking Points for anticipated questions from media, dated 11 Feb 91.
- EFMB Study Guide
- Le Masque A Gaz M17 Article.
- PS Magazine Issue 207
- Treating Chemical and Biological Agent Casualties Lesson 1: Chemical Agents and Protection From Chemical Agents
- FM 34/FMFM 11-9, NBC Protection
- Field Management of Chemical Casualties Handbook (3rd Ed. ), page 200
- CWC Wikipedia page.
- Gas Mask Mooks - TV Tropes