Altimeter, Sensitive, Type C-12, 50,000 ft, US Army Air Force WWII JU-88 which replaced the larger AFN

which replaced the larger AFN 1

The clock is wound by turning this red knob counterclockwise from its home position

It is full of illustrations and diagrams

left or right

as used in the US Army Air Force's Boeing B-29 Superfortress (see photo of B-29 Flight Engineer's instrument panel with a red dot showing instrument location)

Altimeter, Sensitive, Type C-12, 50,000 ft, US Army Air Force WWII JU-88 which replaced the larger AFNHere is an early WWII era Sensitive Altimeter, Air Corps US Army Type C 12, made by Conn. 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. It has a serial number prefix AF 43, evidence of a manufacturing year 1943.