Directional Gyro / Turn Indicator, Type C-1 Sperry 657069, US Army Air Force
Here is an electrical Directional Gyro/Turn Indicator marked AF USARMY (Air Forces US Army), Type C-1. According to the Maintenance Interchangeability Cross Reference Charts of the Air Forces US Army, the C-1 Directional Gyro was used in versions of the Curtis P-40N Warhawk and Bell P-39N Airacobra Fighters and the A-30 Martin Baltimore light bomber.
The left knob rotates the course setting indicator, a small pointer which travels the perimeter of the compass card. The right knob locks and sets the compass card.