Temperature Indicator, Dual Engine, Oil or Coolant, -70 to +150d C, AN5795-6

The Army/Navy Type AN5795-6 Dual Engine Oil or Coolant Temperature Indicator was used across a number of US Army Air Corps, Navy, 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 indicator was made by Edison, part number 33203, and has a serial number prefix of AF43, indicative of a 1943 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. 

See the spec sheet in the photo gallery from the Index of Army Aeronautical equipment Volume 6 Instruments, dated 1944.    

It is in good condition given its age.  Measures 3.25 inches diameter and ~3.25 inches deep.