Voltmeter, Test Meter, WWII Japanese Military

This is a Japanese Voltmeter, Test Meter.  It has two measurement scales, 0-5 volts, and 0-150 volts. It is presumed to be a WWII-era instrument used by the Japanese Army or Navy. This has not been verified. 

It is in good condition given its age.  Measures 2.5 inches wide, 3.5 inches tall, and 1.5 inches deep. The glass and case are intact and the lettering is distinct.