U.S. Army M3A1 Diaphragm Gas Mask

The U.S. Army M3A1 Diaphragm Gas Mask was an updated version of the U.S. M3 Diaphragm Gas Mask, with blue/green plastic parts instead of metal. This example was made by General Tire & Rubber in 1943.
Similar masks in my collection: U.S. Army M3 Diaphragm, U.S. NORBA Type A-3, U.S. ND Mk IV