The ShMS (Russian: Шлем-Маска Специальная - "Special helmet mask"), sometimes erroneously referred to as the SchMS, was a Soviet optical gas mask issued to snipers and artillery crew during the Cold war.
The ShMS uses the standard Russian 40mm thread design to attach a filter and/or hose, and was issued with a standard EO-16 "coffee can" filter. This gas mask is almost identical to the PRVU.
Like other Soviet gas masks made during the Cold War, the ShMS was made in both grey and black variants. The ShMS has a voice emitter at the lower front area of the mask, which is covered by a protective metal cover with multiple holes. The voice diaphragm is fairly standard for the time, using a thin piece of plastic below the metal protector piece to amplify speech. The mask lacks an oral-nasal cup, much like other Soviet masks during the Cold War and as a result, the mask's lenses fog up fairly quickly. The lenses of the ShMS are positioned so that soldiers can look through various optical devices while wearing the mask.
This mask is currently in use by the Syrian armed forces as the standard gas-mask for their NBC squads.