Fuel Quantity Indicator, 4 Tank, Liquidometer, EA-48-17, B-29 Superfortress

This is an authentic WWII-era quad-tank Fuel Quantity Indicator made by Liquidometer, PN EA-48-17, 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). 

According to the B-29 Flight Manual dated May 1945, each of the four engines in a B-29 had four main fuel tanks in the wings (not counting any auxilliary/droppable tanks).  The Outboard fuel tanks, numbers 1 and 4, had a capacity of 1361 US Gallons each, while the Inboard fuel tanks, numbers 2 and 3, had a capacity of 1436 US Gallons each.  The knob situated below the display on the indicator rotates the fuel tank display 1 thru 4 (see photo of display partially rotated), indicating the quantity of fuel in each from 0 to 1320 gallons in tanks 1 and 4, and 0-1415 gallons in tanks 2 and 3 (see photos showing different displays between tanks 1 and 2). The difference between the manual and the indicator is to allow for the potential differences due to fuel expansion resulting from changes in temperature and pressure.