The M6-12-8 Gas Mask is a rare American gas mask, with it being manufactured towards the end of the war, starting in 1944.
This mask used a reclaimed, coated canvas duck muzzlepiece equipped with one large, glued-in, slightly bulged, cellulose acetate eye lens. The M6 fitted over the face and muzzle of the dog. The outlet valve is located directly under the muzzle. The mask was later declared obsolete in 1969, as it would no longer fit the dogs used in use by the time of the Vietnam War.
During World War II, military working dogs were used in the theaters of war by many nations, including the United States, being used for guard duty and mine detection. At that time, the threat to animals included diseases, on top of the combat threats. Due to this, several experimental protective masks were tested for dogs, including the M6-12-8. In 1944, the M6-12-8 was standardized as the "M6" gas mask.