Oil Temperature Indicator, Dual Engine, Type A-24 US Army Air Corps WWII
The Army Type A-24 Dual Engine Oil Temperature Indicator was used across a number of US Army Air Corps and Air Force aircraft during WWII, including heavy bombers B-17, B-24, B-29, medium bombers B-25 and B-26, as well as light bomber A-20, according to the Accessories Interchangeability Chart dated Feb 1945. This A-24 was made by Weston, part number 103107, and has a serial number prefix of AC 41, indicative of a 1941 manufacturing date. This one is labeled for Left and Right engine, so it may have been used in a twin-engine bomber such as the B-25, B-26, or A-20, or transport aircraft such as the C-46 or C-47. Embossed on its face is "AC USARMY" (see close-up photo), clearly made for an Air Corps order. The remnants of red and green paint can be seen on the glass, to indicate the operating limits of the aircraft in which it was last installed.
See the spec sheet in the photo gallery from the Index of Army Aeronautical equipment Volume 6 Instruments, dated 1944. The instrument displays oil temperature from 20-120 deg C for each engine.
It is in good condition given its age. Measures 3.25 inches diameter and ~3.25 inches deep.