The filters are designed to filter out toxic or radioactive vapors or aerosols, as well as biological agents. Although the filters are similar to and have the same 40 mm threads as the GP-5 gas mask, they are a slightly different design, having a sloping top with ridges stamped into the metal.
Drinking system
The PMK gas mask contains a drinking tube, allowing soldiers wearing the mask to rehydrate without removing the mask itself. The system consists of a special canteen cap, which will only allow water to flow through when connected to the tube leading to the mask.