Boost Pressure Gauge, -7 to 16 PSI, Mk IIIK
This is an authentic WWII-era Boost Pressure Gauge Mk IIIK, indicating supercharger pressure from -7 to 16 PSI, as used in aircraft of the British RAF and the Royal Australian Air Force. It has a serial number indicating a year of manufacture of 1941.
According to the guide "RAAF 346 Types and Locations of Instruments", the Mk IIIK Boost Gauge was used in versions of the Spitfire and Mosquito.
This example is clearly experienced. There is a crack on the rim/ring. Measures 2.5 inches diameter and ~2.5 inches deep. This is an inexpensive way to own a relic of some infamous aircraft.