The Navy MARK I was one of the earlier masks made by the United States, not to be confused with the later optical MARK I made in WWII.

Most resources will point to the date of manufacturing being around 1917-1918, around the same time as the C.E.M. The mask was designed to take the elements of the British Small Box Respirator and the German Gummischutzmaske and make a comfortable and mobile mask during the first world war.

Similar to the Gummischutzmaske, the MARK I was issued in a metal canister. However unlike the German Gummischutzmaske, the MARK I used a wide rubber flapper type exhale valve that protruded from the filter inlet stem. Like the C.E.M, The Navy Mouth Canister mask used nose clips and a snorkel like mouth piece on the inside. Unfortunately there are few pictures of the MARK I, as it is a scarce and valuable mask.

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