Gyro Horizon OV-1 The compass card containing the

The compass card containing the markings of the compass rotated to indicate magnetic north as it received signals from the master unit (in the Lanc

From Air Navigation Technical Manual TM 1-205 1940 US Army Air Corps (the reference call-outs refer to the diagram in the photo gallery reproduced from this manual):

Per a colleague

This example is likely made for aircraft of the Royal Canadian Air Force

Gyro Horizon OV-1 The compass card containing theThis is a pre WWII era Gyro Horizon (Flight) Indicator, Army Type C 5, made by Sperry, part number 643770, marked for the Air Corps US Army. This indicator has a serial number prefix "AC 40", evidence of a manufacturing year 1940, prior to the US entering WWII. The C 5 Gyro Horizon was used across all aircraft of the US Army Air Corps, including bombers B 17, B 24, B 25, fighters P 38, P 40, P 47, P 51, and transport C 47. The Gyro Horizon provided