The PMK-3 is the current-issue gas mask of the Russian Federation Armed Forces (as of 2013). The mask is designed to protect against CBRN threats and is an improvement over the PMK-2 and PMK-1 gas masks.
During the 1990s work began on a project to replace the PMK-2 gas mask which was the current-issue gas mask of the Russian army. Due to the PMK-1 having the capability to mount filters only on one side, the PMK-2 and the PMK-3 were designed to mount filters on either side to accommodate left-handed shooters. The Russians, designed their new masks to have detachable ports which will be installed by the user based on preference. Unlike most masks which use two readily-installed filter ports on both sides, the PMK-2 and PMK-3 were required to be backwards compatible with older Russian filters and have the capability to mount 40mm GOST filters. In addition to this requirement, the arrival of the new generation PMK-2 and 3 filters (needs citation), which provided improved protection in a smaller package, caused a design turn as the new generation Russian filters used a proprietary connector. This meant that the PMK-3 gas mask had to be able to use two kinds of filter interface connectors on either side. The solution was to have a detachable adapter connector for 40mm GOST filters and an open port to accept the new generation Russian filters. The advantage of this was that the PMK-3 would be able to use two different kinds of filters however, because of design limitations, mounting the filter ports on the mask requires a lot of effort (it uses friction to form a seal and no glues or adhesives) and filter changes are difficult and most require the user to remove the mask if using the proprietary new-generation Russian PMK-3 filters.
To use the PMK-3, the user must first select the preferred filter type. If the PMK-3 filters are to be used, then the user will simply mount the PMK-3 filter on the preferred side of the mask. If the user wants to use a 40mm GOST filter or an older PMK-1 filter, then he/she must take the provided plastic 40mm adapter (part of the kit) and mount it on the selected port. Once this is mounted, the user can now screw-on GP-7 or GP-5 gas mask filters on the adapter. A blanking plug is also provided which the user must mount on the unused filter port. After this, the user can now don the mask and it will provide the protection offered by the filter used.
The PMK-3 is a big improvement on the PMK-2 as it features larger eye pieces and a screw-mounted canteen adapter which allows the user to use a drinking canteen through the provided PMK-3 drinking tube without pushing the drinking tube against the canteen to allow water to flow through the shuttle valve. Since backwards compatibility was one of the chief considerations during the design phase, the PMK-3's drinking tube accessory can interface with older Russian drinking canteen sporting the shuttle valve cap. The mask also has the usual ballistic outserts (not interchangeable with the PMK-1 and 2). The mask appears to be made of butyl rubber (needs citation). Like the PMK-1, the PMK-3 comes with a new filter sock that is used to cover the filter during use in heavy snow. The purpose of the sock is long believed to be for added camouflage and snow cover but some collectors have claimed that the sock itself acts as the particulate filter of the canister as some gas mask training manuals found in post-soviet bloc countries suggest and that this is the true purpose of the sock (needs citation). This is very difficult to confirm as there is little official or manufacturer information available to the public regarding the exact purpose of the filter sock and the PMK-3 masks don't come with user's manuals either. The new filter sock also includes a plastic spacer which creates internal clearance and increases filter efficiency unlike the old filter sock which slightly obstructs air passage. One peculiar thing on the PMK-3 and its filter is that the inhale valves are on the filter and the adapter--- not the mask itself. So replacing the standard PMK-3 filter will provide a new intake valve with rubber disk. Like the PMK-1 late generation (or GP-7VM) and PMK-2, the PMK-3 comes with metal parts unpainted or un-oxidized. This makes the mask's metal parts appear in light-gold color for the eyepiece frames, voice diaphragm and interior metal parts. It is unclear what the lightweight and chemically-resistant alloy comprising the metal parts is.
The PMK-3, because of it being a current-generation mask, is rare outside of Russia. Also, it is speculated that because the mask is made post-USSR breakup, there are less units made as Russia no longer has to accommodate USSR-bloc countries in mask production runs.