Oil Pressure, Dual, Set for 4-Engine Aircraft, Type B-9A USSR The knob adjusts the indexing

The knob adjusts the indexing 'aircraft' within the dial to align the perspective of the pilot to the horizon indicator

This type of communication

This is an exceptional example of a remote-indicating Course / Directional Gyro Indicator as used in the 1950's Korean War-era MiG-15 jet fighter and other aircraft of the USSR's Soviet Air Force

According to the Maintenance Interchangeability gude dated Feb 1945

Oil Pressure, Dual, Set for 4-Engine Aircraft, Type B-9A USSR The knob adjusts the indexingHere is a set of WWII era Type B 9A Dual Oil Pressure Indicators, as used in four engine of the US Army Air Force such as bombers B 17, B 24, and B 29 and transport C 54. These are Bendix Autosyn indicators, which used pressure sensors at the engines which electrically transmitted the signal to these electrical indicators. Both are labeled "AF US ARMY" on their faces. The indicator marked for engines 3 & 4 has a 1944 manufacturing serial number