Engine Temperature Indicator, 0-350deg C, Mk I, 6A/620 RAF Air Ministry Canberra or outside air temperature

or outside air temperature

000 meters

The US Army Air Corps fighter P-39 Airacobra is an example of an aircraft which used this venturi

There are two pointers

and ~1/2 inch thick

Engine Temperature Indicator, 0-350deg C, Mk I, 6A/620 RAF Air Ministry Canberra or outside air temperatureThis is a fine specimen of a WWII era British Engine (or Cylinder Head) Temperature Indicator, Mk I, type 6A 620, indicating up to 350deg C for each engine, as used in aircraft of the RAF, RCAF, and RAAF. According to the guide Types and Location of Instruments in RAAF (Royal Australian Air Force) dated 1943, which cross references to those used in RAF aircraft, the 6A 620 was used in Beaufighter (using 2) and the patrol bomber seaplane Short