Small box respirator

A small box respirator, or gas mask, dating from World War I. The respirator is comprised of a metal canister, hose, and face piece. The metal canister is painted yellow and has horizontal ridges throughout. Two texts are stamped on either side of the hose on top of the canister, they read, [135XH] and [CANGO]. [CANGO] is also stamped in a circle on the front of the canister. The canister is connected on top by a circular opening to a textile covered hose. The hose connects to the face piece by a black valve with an opening at the bottom. The face piece is made of green canvas and lined with rubber that has mostly deteriorated. The hose connects to an inner mouth piece and a nose clip inside the mask. It has glass goggles and black adjustable straps attached to the back. The glass on the goggles has corrosion and deterioration. The top head strap has been cut off.