U.S. Navy MkI Gas Mask

Recently we were able to get our hands on a very scarce U.S. Navy MkI gas mask!  These masks are basically a German Gummimaske M15 mask ‘shell’ with the Corrected English Model‘s internals (such as mouthpiece and flutter valve).  Another peculiarity of this mask is that it uses cylindrical filters—similar to the German Lederschutzmaske M17, German Gummimaske M15, and the French Appareil Respiratoire Spécial (A.R.S.-17) masks.  You’ll see what I mean when we take a look at the photographs.
The MkI gas masks were made late in America’s involvement of the war, and so were (and are) scarce.  The Navy used these on the ships for training purposes, but it’s also thought that some Marines would’ve been equipped with these.  Whether or not these Marines, if they had even been issued to them, would’ve had them in any front-line duty, is unknown.  This mask and its history is enigmatic, seeing as to that it was a rather rare mask then and is an even rarer mask now.

The front view of the U.S.N. MkI mask.  It looks like a Corrected English Mask with German filter.  Unlike the the Lederschutzmaske and artillery model A.R.S.-17 mask, the lenses aren’t reinforced.  The tag to the right is the original inventory tag.
Internal view of the U.S.N. MkI mask.  Notice the nose clamps, mouth piece, and straps—straight from the Corrected English Model and later R.F.K. masks.  Luckily, this mask is still a bit pliable and is not completely dry-rotted.
Underside view of the U.S. Navy MkI mask.  The little slit between the filter and mask itself is the ‘flutter valve’ (which I believe is to catch spit), which are ⅞ times missing.  I do not know what the ‘C’ ink mark on the filter means, but if someone knows I’d love to know.
The view of the bottom of the filter—basically your standard gas mask filter.  As for the contents of the filter, I cannot say for sure.  However, the box respirators (of which the C.E.M. is a member) were commonly filled with chemical-impregnated cloth, activated charcoal, and even asbestos.
The canister of the mask.  It is a basic sheet-metal canister made of rather thin metal.  The canister would’ve easily been battered-up in the field.
A view of the U.S. Navy ink stamp.  It’s a bit faded, sadly.