Czechoslovak 42mm filters

Filters listed in this article are known to contain materials hazardous to health Exercise caution when handling and storing. Refrain from using these filters. Seek medical advice if you have any concerns.

In the 30s, the Czechoslovak gasmask industry was booming, and many companies started making masks on their own, with which came the need for more filters. Thus, many of those small companies started making filters as well, resulting in a variety of them. All of the filters listed are 42mm. All filters were also sealed with a metal thread-on cap from the top, and most of the time a strip of fabric tape at the bottom.

Marking of the filters: The filters are almost always marked S-XXX-XX. The S stands for Series, first number for the batch number, second number for the last two digits of the year.

Example - S-52-38 - Series/batch number 52, made in 1938.

They also have a precise date of manufacture stamped, as per regulations, either on the top or on the bottom. If the filter was made before the annexation of Czechoslovakia, it has the approval seal sporting the national lion, if made during the war, it either has waffenamts, or nothing. Sometimes there's a precise filter number stamped as well.

Example - If the number 1672 is stamped on a filter, then it's the 1672nd filter of the batch.

The filters are divided into four main categories :

• Small filters, meant to be screwed directly onto the mask
• Large filters, meant to be attached to a hose
• Training dummy filters, only filled with deadweight, often marked by odd colors
• Special filters. This category contains filters that didn't really fit any of the previous ones, or that have markings with an unclear meaning

Small Filters

Eckhardt Filtr - 2

The most common filter on the Czech market. Most of the times sold with non-Eckhardt masks; even though Eckhardt did produce its own masks, they were never very successful. The EF-2 can be recognized by an "EF-2" stamp on the top of the filter, alongside the Eckhardt logo.

Chema Filtr CHF 1/KL Filtr

Also quite common, sold both with Chema masks and others. it's distinguished mainly by the stamping on the bottom. There's always the Chema logo and either a KL ink stamp or "CHF-1".

A regular 1937 made CHF-1

Unidentified Chema Filter

Unidentified Chema filter (included for the sake of completeness)

Chema KU Filtr

A universal filter. Sold with the Chema C - Lidová masks.

Horák-Titán Vzor 23

The standard-issue filter for the Vz.23 gasmask, made by Horák-Titán a.s. . The thread is 42mm, it's one of the first domestically produced by the newly independent Czechoslovakia. Used from 1923 until 1935 as a military filter, and until 1939 as a training filter along with the Vz.23 gasmask.

A Vz.23 filter. Painted red, either because it was used as a training filter, or because it was made as a firemen filter.

Horák-Titán Model 31

There were multiple models of said filter, differing by the chemical agent they were meant to protect against. The agent it protected from was indicated either by the color of the filter, or a strip of paint on the filter.

Markings :

• Conventional gasses - Light green, marked with an O.
• Halogens, bromine, iodine - Dark green, marked with a H.
• Ammonia - Black, marked with an A.
• Smoke and gasses appearing because of a fire (excluding carbon monoxide) - Red, marked with a P.
• Hydrochloric acid, nitric acid, sulfur dioxide - Yellow, marked with an S.
• Hydrogen sulfide - Yellow, marked with an SV.
• Vapors - White, marked with an M.
• Phosgene - Pink, marked with an F.
• Hydrogen cyanide - Blue, marked with a K.
• Zyklon B - Blue, marked with a C.

There was then an updated set of markings rolled out a few years later.

• Vapors from paint thinners - Light green, marked with an O.
• Halogens, bromine, iodine, hydrogen chloride, hydrogen bromine, hydrogen iodine, hydrochloric acid, nitric acid, sulfuric acid, sulfur dioxide - Dark green, marked with a H.
• Ammonia - dark brown, marked with an A.
• Smoke from a fire - Red, marked with a P.
• Hydrogen sulfide - Yellow, marked with an SV.
• Vapors from zinc, mercury, etc - White, marked with an M.
• Phosgene - Purple, marked with an F.
• Hydrogen cyanide, Zyklon B - Light blue, marked with a C.

• All of the gasses listed above except for Carbon monoxide, Carbon dioxide and Hydrogen sulfide - Striped (green-brown-green), marked with a U (for universal).

• Carbon monoxide and all gasses which contain it - Grey, marked with CO.

All of the markings above, both the earlier and later ones, apply for the larger Model 32 filter aswell. The original price was 40 Kc.

Picture taken form an original promotional brochure

Pála Filtr

Designed and produced by Pála a.s. . Regular 42mm filter, slightly stubbier compared to other ones.

Doležal-Plyma DF-1

Plyma's very own attempt at a gas mask filter. Few are known these days, just like everything made by Plyma.

Fatra P

Very similar in appearance to the Vz.23, differs only in the marking. Made by Fatra.

OF-2

Not very much is known about who created it, or what the OF stands for (it could be Ochranný Filtr, it could also be Optimit Filtr, nothing proven as of now)

Techna Filtr - 1a

Sold either with Techna's own masks, or separately.

Techna Filtr - 3

A successor of the Techna Filtr 1.

Techna Univerzální L

An early production TF-1a . Some are found with Fatra stickers attached to them, the meaning of that is currently unclear.

Mars Ocelový Dům Filtr 1

Filter either manufactured or just branded by Mars/Ocelový Dům a.s. reminiscent of french Poelman filters. Sold with Mars' own Leyland masks. (note that the nomenclature shown above is possibly inaccurate)

Eckhardt UF

A rather stubby filter compared to other Czech ones of the time. Sold both by itself and with Eckhardt masks. The meaning of the acronym is not known yet.

Eckhardt UFR

Very close in look to the EF-2, differing only in a small rib. Again, the meaning of the acronym isn't known yet. They are rumoured to be specialized industry filters, but no info has surfaced yet on their use.

Eckhardt EX

Most likely yet another specialized filter. Very close, if not identical in appearance to the UFR. They're found mostly in Spain and dated 1937, usually issued with masks used by the Bando republicano. Furthermore, some are found with Fatra stickers.

Spanish sample

Eckhardt FF

Another (most likely) specialized filter. Similar in appearance to the EF-2, except this time,ribless.

Salus Filtr

A universal filter. Not much is known about it, besides the fact that it was sold with the Salus S (Salus) mask.

Prometheus BH

A filter made by a very small company for use with the Prometheus Typ 1 masks.

Large Filters

Chema Vz.27

The standard filter for the Vz.33 and Vz.35 gasmask. Carried in a haversack, connected to the mask via a hose.

Eckhardt Filtr - 1

Eckhardt's main large filter. Carried in a harness of sorts, either on a strap, or attached to the user's belt.

Eckhardt UFS

Most likely also a specialized filter of sorts. In appearance identical to the EF-1, differing only in the "E" stamped on the bottom.

This particular filter was exported in Spain during the Spanish Civil War. The label means it was recovered and reused after the end of the war.

Techna Filtr TF-2

Later production Techna S

Horák-Titán Model 32

An upscaled version of the Model 31, said to contain four to five times as much of protection, thus last four to five times longer (claimed in sales brochures). The original price was 60 Kc.

Unnamed Chema Large Filter

As the title suggests, the name of this filter is not known. It's only known that it was produced by Chema in the 30s and that it is 42mm.

Techna Univerzální S

Techna's large filter, often seen with Samaritan masks. Attached to the user's belt via a cloth harness.

Chema BS (Samaritánský)

A large Chema filter sold with the so-called "Samaritan" kits, intended for the samaritans (a voluntary medical corps of sorts, working in close conjunction with the cPo). Has extremely low resistance. Green in color, marked with a red cross. Has a rib in it's lower half.

Unidentified Large Chema Filtr

Yet another unidentified large Chema filter.

Zbrojovka Vsetín CO Filtr

An anti-carbon monoxide filter made by a weapons company, Zbrojovka Vsetín.

Chema CO Filtr

An anti-carbon monoxide filter made by Chema.

Chema E-Filtr

Visually very akin to the EF-1. Made by Chema.

Eckhardt CH-Filtr

Also visually akin to the EF-1, however different from the bottom and in markings.

Mars Ocelový Dům a.s. Ochranný Filtr - 1

Mars' large filter, sold both separately, and with samaritan masks.

Training Filters

Chema KC

Painted in either a vibrant blue color to avoid being mistaken for an actual filter during an air raid, or otherwise light gray (most likely for the same reasons). The filter has a massive sticker on its lower part saying "Cvičný Filtr" (Training Filter). These filters continued being manufactured even after Czechoslovakia became a part of the German Reich, as shown by the 2nd picture, where the words "Cvičný Filtr" have been translated into German (Übungsfilter)

Regular pre-war Czech variant

Wartime variant, with German wording.

The less common light gray variant. Also pre-war

Fatra Cvičný Filtr

The most lucent among the filters mentioned, being sold either in gold or silver color. It has a fake inward rib and is filled with dummy weight. The filters also had actual valves. Sporting only a "Fatra" sticker, and a big block of text on a paper sticker on its lower third. The text reads - Cvičný Filtr I. Používejte jen ku cvičení. Nechrání proti plynu! (Translation - Training Filter I. Use only for training purposes. Does not protect against gas!). The filter weighs about as much as an actual one.

Gold variant, light grey from the bottom. The valve is missing on this particular example, however, note the valve notch where it would've once sat.

Silver variant.

Doležal-Plyma Cvičný Filtr

Painted a once-rich dark blue color, to stand out against actual, usually green or grey, filters. It has markings. Also, it has a strip of paper in the middle that reads - Cvičný Filtr. Nechrání proti plynu! (Training Filter. Does not protect against gas!).

Techna L (Cvičný Filtr)

Techna's training filter, unlike most other ones, either light gray or green, thus blending with the other ones, however, they had big blocks of red and yellow text. There are two different models, both shown under this text. The text (either above or below the main text) reads - NECHRÁNÍ PROTI BOJOVÝM PLYNŮM (DOES NOT PROTECT AGAINST WAR GASSES). The main text reads - Techna L, Cvičný.

Green shorter variant

Light gray taller variant.

Eckhardt CF

There were three variants, all marked CF (Cvičný Filtr). A short one, a taller one, and the tallest one which resembled the EF-2. Text reads - Cvičný Filtr. Používejte jen ku cvičení. Nechrání proti plynu! (Translation - Training Filter. Use only for training purposes. Does not protect against gas!). They also had a seal of protection (shown on the smallest one) reading Ochranná Známka Eckhardt, or Eckhardt's seal of protection (patent-wise). All of them came in silver.

Smallest version. Note the seal.

Intermediate version.

Tallest version, closely resembling the EF-2.

Mars Cvičný Filtr

Mars' training filter, visually resembling their actual filter. Silver coloured. The text reads - Cvičný - Nechrání proti plynům - Cvičný - (translation - training, does not protect against gasses- training)(repeats around the whole filter).

Pála Cvičný Filtr

Short filter, silver-coloured, marked only with Pála's logo of a man in a gas mask.

Ypra/Kudrnáč Cvičný Filtr

Light-blue coloured filter. Has Ypra's Leyland logo with the overlayed text, since Ypra products are Kudrnac products under a detached brand, owned by the same person. Price was 25 Kc new.

Special Filters

Eckhardt Hasičský

One of the multiple fireman-specific filters. Marked by an "H" stamped on the top.

Marked with an "H" along with the company name. Made during the 2nd world war, thus devoid of proof marks. This particular one was found in an old fire station, along with the next filter and a plan of the station from the 30s.

Chema KH

Chema's earlier firetroop filter. Based on the Chema KU.

Chema CHF-1 (H)

Also presumed to be a fireman filter, because of the red color, and where it was found. Stamped CHF 1 on the bottom, along with the company name.

Note the signature of the previous owner on the left image.

Eckhardt UFH

Yet another fireman filter, this time from the UF series of specialized filters. Marked with "UFH" in bold letters on the top, painted in the same red color as the rest.

Chema KP

An industrial filter based on the KU. The P stands for "Průmyslový". Sold in multiple variants with varying marking.

Unknown Filter

Filter of unknown origin. Marked with only the date.

Unknown Eckhardt Filter

Unknown Eckhardt filter. Most likely a training filter, that would explain the "ports" in the side.