Swiss GM 33
The Swiss FEGA Gummimaske 33 was the primary gas mask of the Swiss Army during World War II. It was made of green rubberized canvas, and the filter was attached to a long corrugated hose. This example was made by Feuerschutz Gasschutz around 1933.
Gummimaske = "Rubber Mask"
Feuerschutz Gasschutz = "Fire Protection Gas Protection"
Similar masks in my collection: Swiss C-Maske