Scott Sky Mask
The Scott Sky Mask consisted of a nose cup made of rubber-like material, a replaceable breathing bag, and a long hose to be connected to an oxygen tank. It was used by pilots of small aircraft, and proved efficient up to 34,000 feet. This example has hardened over time and become oily and brittle. It was made by Scott ATO in the 1970s.
Similar masks in my collection: Scott Airline Passenger Mask