U.S. Army M2-10A1-6 Lightweight Optical Gas Mask
The U.S. Army M2-10A1-6 Lightweight Optical Gas Mask combined elements of the earlier U.S. Army MI-I-5/U.S. NDO Mk I and the M3/M4 Lightweight Service masks. This example was made by Continental Rubber in 1952.
Similar masks in my collection: U.S. Army MI-I-5, U.S. NDO Mk I, U.S. Army M3 Diaphragm, U.S. Army M3A1 Diaphragm, U.S. Army M3-10A1-6, U.S. Army M4-10A1-6