This authentic vintage electrical Dual Engine Tachometer, United States Army Air Forces Type E-14, AN-5530-2, manufactured by the Chicago Flexible Shaft Company of the General Electric Design 8DJ19, was ubiquitous in its use in WW2 USAAF and US Navy aircraft. According to the Maintenance Interchangeability Chart TO No 00-25-29 dated December 1943, the E-14 Dual Tachometer could be found in the iconic bombers B-17, B-24, B-25, B-26, twin-engined fighters P-38 and P-61, as well as transports C-46 and C-47.

The Dual Engine Tachometer appeared on the instrument panel of the cockpit and/or, sometimes in the case of bombers or transport aircraft, the instrument panel of the flight engineer. It would be attached to a Tachmeter Generator located at each engine, indicating engine (propeller) RPMs from 0-4500. The dial contains two pointers, one for engine 1, the other for engine 2. In four engine aircraft, two dual tachometers would be present, the 2nd to indicate RPMs of engines 3 and 4.