U.S. Army MIAI Training Gas Mask
The U.S. Army MIAI Training Gas Mask used a molded rubber facepiece with blue/green plastic parts, MV type exhale valve, and its filter mounted directly to the chin. As the Army stopped using Roman numerals, the nomenclature of this mask was later changed to M2A1. The first example was made by Firestone in 1941, and the second example was made by Acushnet in 1941.
Manufacturer and date stamp
Date and lot stamp on reverse side of exhale valve
Lot number stamped on head harness
Close-up of bag for Training Gas Mask MIAI