Ammeter/Voltmeter, WWII Japanese Aircraft Douglas and US Navy versions R4D

and US Navy versions R4D 6 & 7

The H-4 was equipped with a boom mounted microphone M-6A/UR to be used below 10

This is a fine specimen of a WWII-era British Engine (or Cylinder Head) Temperature Indicator

It has date stamp of January 1951 and Boeing tamper evidence seals

Fuel Quantity Indicator

Ammeter/Voltmeter, WWII Japanese Aircraft Douglas and US Navy versions R4DThis is a Japanese Voltmeter or Ammeter. The scale is labeled to a value of 2. 0, and "2000V" is embossed in small lettering in the upper right of the dial, so we aren't sure of the exact function or application. 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 has the "YEW" symbol of the Yokogawa Electric company on