Oil Quantity Indicator, 4 Tank, EA-48-16, B-29 Superfortress A4 Skyhawk the ring is turned until

the ring is turned until the two white wires are parallel to the North-South lines on the card

the manual describes the instrument's use

75 inches diameter and ~1 inch deep

Navy’s contractual requirements

The glass and all markings are intact

Oil Quantity Indicator, 4 Tank, EA-48-16, B-29 Superfortress A4 Skyhawk the ring is turned untilThis is an authentic WWII era quad tank Oil Quantity Indicator made by Liquidometer, PN EA 48 16, 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). Each of the four engines in a B 29 had an 80 gallon oil tank in the nacelle with a 5 gallon expansion space. The knob situated below the display on the indicator rotates to the oil tank display 1 thru 4,