Cowl Flap Position Indicator, Bendix Magnesyn, C-121 Lockheed Constellation
This is a dual Cowl Flap Position indicator as used in the US Air Force C-121 transport version of the Lockheed Constellation. See photo of the location of the instrument on the Flight Engineers upper instrument panel from the C-121 flight manual dated 1958. It has a date stamp of Dec 1956 on the side case. Measures 3.25 inches diameter and ~3 inches deep.