Flap Position Indicator B-24 Liberator, PB4Y Privateer, WWII GE DJ11
This is a Flap Position Indicator as used in the WWII-era Consolidated US Army Air Force B-24 Liberator Heavy Bomber (see 2 cockpit photos and photo from the B-24 Pilots Manual dated 1944) and the US Navy's PB4Y4 Privateer Patrol Bomber (see photo from Flight Manual dated 1945). Made by General Electric, Type DJ11.
The indicator provided visual information on the angle of extension of the wing flaps during take-off and landing, measured from full up at 0 degrees to 40 degrees fully extended downward. Measures 2.25 inches diameter by ~2.5 inches deep.