Temperature Indicator Type AN-5790-6: P-51, B-17, P-38, P-40, P-47

Here is an authentic WW2-vintage Temperature Indicator type AN-5790-6, as appeared in the WW2 Fighters P-51D Mustang, P-40 Warhawk, P-47 Thunderbolt, and P-38 Lightning, as well as Bombers B-17 Flying Fortress and B-26 Marauder, and various aircraft of the US Navy and Marines. Made by Hickok, it was used to measure coolant temperature, carburetor air temperature, or outside air temperature, and the label of those locations would be added directly to the instrument panel instead the instrument itself.  It measures 2.25in diameter and 3in deep.