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 Sutton-Horsley, part number 2213-7, and has a serial number prefix of AF42, indicative of a 1942 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.
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.