Manning, Maxwell, & Moore
Gun Sight Mk 15 Air Pressure Check Gauge US Navy
The Air Pressure Check Gauge was used with the Sperry gyroscopically-stabilized Mark 15 Gun Sight, which was used on 40MM Antiaircraft Guns on ships of the US Navy late and post WWII.
The Sperry Mark 15 Gun Sight contained a gyroscope which was pneumatically-powered by an external compressor. This gauge was used as a check by the gun crew to ensure that the pressure would provide accurate gyroscope stabilization.
It is in exceptional condition given its age. This example has a date stamp of March 1953. Measures ~2.5 inches square and ~1.75 inches deep.