Voltmeter, 15V, WWII Japanese Aircraft
This is a Japanese Voltmeter,15V. It is presumed to be a WWII-era indicator used in aircraft of the Japanese Army or Navy. This has not been verified. Aircraft that may have used this have not yet been identified.
It is in good condition given its age. Measures ~2.5 inches diameter and ~1.5 inches deep. The glass and case are intact and the lettering is distinct.