The Model IV was a Dutch gas mask, produced from 1938 until the German invasion in 1940. At first, it was called Model H, but that was confusing, because the navy also got a gas mask called Model H, so it got renamed. It was the first army gas mask that used a threaded filter, instead of a hose. The mask had an adjustable rubber band at the bottom, to create an adjustable chin rest. The head harness was 5 point, with a fabric piece at the back for comfort. For some reason, the mask was only produced in size 5, which is the largest size.
Gallery
Inside of the mask, note the adjustable chin rest
The fabric head harness piece
Valve assembly
Canister
Manual