Voltmeter, 1500V, WWII Japanese Aircraft Constellation The problem with using this

The problem with using this indicator was not only identifying the aircraft

as used in the US Army Air Force's Boeing B-29 Superfortress (see illustrations of B-29 Flight Engineer's instrument panel showing instrument location)

dated 1954

whereby a red light would illuminate on the panel if this temp was reached

which is designated by a vertical dash on this one and by a small aircraft silhouette on the I-65)

Voltmeter, 1500V, WWII Japanese Aircraft Constellation The problem with using thisThis is a Japanese Voltmeter, 1500V. 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.