U.S. Military Surplus Optical Gas Mask M1, adopted by the U.S. Army from the late World War I to the early World War II period. After being used jointly with the U.S. Navy, the Navy developed its own gas mask, the USN ND series. From MARK Ⅰ to MARK Ⅳ, and MARK Ⅴ with a changed bag shape, they exist. Other types of gas mask bags are listed separately, so please take a look. This is the carry bag for the optical gas mask, which is almost a phantom item. The insignia of the Army Chemical Warfare Service is stamped on it, and it has a single-hook shoulder strap that was inherited up to MARK Ⅳ, and a unique shape with buttons on both side flaps and the main flap. There are stains, small holes, and scratches on the strap commensurate with its age, but there are no major tears or missing parts, and the stamp is clear. In the first place, there are no existing items, so this is in an extremely excellent condition. Please check the photos for the small holes on the front and both sides, and the scratches on the strap. I am listing it without setting a price, but there is no trace of it being distributed in Japan. Very rarely, if it is listed on overseas auctions, it is in worse condition than this (dirt and damage that makes it difficult to identify the stamp, repairs, inscriptions, etc.), and it is questionable whether it can be won for $200. I hope you will refer to this and make an offer. External dimensions: Approximately 26x19x16 cm Strap length: Approximately 145 cm (maximum)