Altimeter, Sensitive, Type C-12, 50,000 ft, US Army Air Force WWII Mosquito which cross references to those

which cross references to those used in RAF aircraft

Sweeting’s book "Combat Flying Equipment":

Must have been a high pressure application judging from its construction (number of screws and thickness of lens)

The main dial measures time

G Mitchell

Altimeter, Sensitive, Type C-12, 50,000 ft, US Army Air Force WWII Mosquito which cross references to thoseHere is an early WWII era Sensitive Altimeter, Air Corps US Army Type C 12, made by Conn, part number 80000. The C 12 Altimeter was used across all aircraft of the Air Corps US Army, including heavy bombers B 17 and B 24, medium bombers, B 25 and B 26, Fighters P 38, P 39, P 40, P 47, and P 51, and transports C 46 and C 47, according to the Maintenance Interchangeability Chart dated Dec 1943. The knob is used to adjust the altimeter to the barometric