Fuel Pressure Indicator, Dual Engine, 0-25 PSI, AN-5772TIA US Navy P-51 The indicator measures the temperature

The indicator measures the temperature of the cylinder head via thermocouple from a single engine

which is designated by a vertical dash on this one and by a small aircraft silhouette on the I-65)

Reference Number 41-7952

A "zero center" ammeter

Fuel Pressure Indicator, Dual Engine, 0-25 PSI, AN-5772TIA US Navy P-51 The indicator measures the temperatureHere is a 1940 50s era dual engine Fuel Pressure Indicator made by Edison PN 34955, for aircraft of the US Navy. See photo showing the yellow USN anchor symbol stamped on its back case. Also, a service stamp has been affixed to its side indicating it was once serviced at NAF DET, or Naval Air Facility Detroit (MI). It may have been used in a dual engine aircraft (such as the PBY Catalina or PBM Mariner), or paired with another in a four engine