Flap Position Indicator B-36D Peacemaker GE DJ-4
This electrical Flap Position Indicator, GE Type DJ-4, Model 8DJ4PFY, appeared in the largest piston-engine (6 of them, along with 4 turbojet engines) bomber ever to see service if the US Air Force: the Cold War-era Convair B-36D Peacemaker. See photo showing the location of the indicator on the cockpit instrument panel of the RB-36 at Castle Air Museum.
This indicator displayed the flap position for each of 3 pairs of flaps: Inboard, Center, and Outboard, from 0-30 degrees of flap (each wing had one flap Inboard, one flap Center, and one flap Outboard). The B-36 flaps were electrically and mechanically synchronized in symmetrical pairs.