Tachometer, Dual Engine, Electric, Type E-10, Engines L & R, Air Corps US Army
Here is an early WWII-era dual engine electrical Tachometer, Autosyn-type, measuring engine revs up to 3500 RPM. The Type E-10, made by Bendix part number 6007-28C-7-A was used across multi-engine aircraft during WWII, such as early versions of fighters P-38 Lightning, medium bombers B-25 Mitchell and B-26 Marauder, transport C-46 Commando, as well as early versions of B-17 Flying Fortress and B-24 Liberator. It is embossed on its face with AC US ARMY, or Air Corps US Army. The pointers are marked L & R, so likely used in a twin-engined aicraft such as the P-38, B-25, or B-26, as well as transport C-46 or trainer AT-21 Gunner.
The glass, dial, and case are intact, and the markings are quite clear. The lettering is raised, providing a nice 3-dimensional appearance on the dial. This instrument has a serial number prefix of AC-42, indicating a manufacturing year of 1942. Measures 3.25 inches diameter by 6 inches deep. It is in exceptional condition for its age.