Voltmeter, 15V, WWII Japanese Aircraft Martin the pointer indicates altitude along

the pointer indicates altitude along the inner green scale

designed for aeronautical use

likely to allow illumination from a light source mounted internally in the dashboard

At almost 200 pages

and a spider-type compensator

Voltmeter, 15V, WWII Japanese Aircraft Martin the pointer indicates altitude alongThis 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.