Autopilot Directional Gyro Kit, Type GR-2, Grumman F7F, F8F US Navy
Here is a Directional Gyro Control Kit for the Type GR-2 Autopilot System made by Electric Auto-Lite for Grumman Aircraft under license from Sperry, according to its markings. The directional gyro is powered pneumatically, and the module mounted on the rear appears to provide electronic sensing of the gyro's position for transmission to the autopilot system, judging from the electrical and pneumatic connections in back. The center knob is to set the desired course and to cage the gyro.
We have only been able to trace the predecessor to the GR-2 Autopilot, the GR-1. The GR-1 was used in the US Navy Grumman F7F Tigercat and the Grumman F8F Bearcat fighters in the late 1940's post WWII. Grumman aircraft after these, such as the F9F Panther, appear to use a next generation autopilot and not the GR-2. So we are hypothesizing that the GR-2 may have been destined for later versions of the F7F and F8F than those supported by our reference documents.