Horsepower Indicator, -500 to 5000 HP, Allison Engine US Coast Guard This is a Carburetor Air

This is a Carburetor Air Temperature Indicator for a dual engine aircraft as used in the C-46 Curtiss Commando Transport aircraft of the US Army Air Forces during WWII and through the 1950-60's by the US Air Force and civilian operators

and the front page of the Collins sales brochure

but is frozen in position in this specimen and may be able to be repaired

and on the B-29 it was installed on the flight engineers instrument panel

Horsepower Indicator, -500 to 5000 HP, Allison Engine US Coast Guard This is a Carburetor AirThis is a Horsepower Indicator, displaying HP from 500 to 5000 HP at 100% RPM. This was manufactured by Hickock Electrical Instrument Co., part number 560 422, also labeled with an Allison Engine part number 6734355A. Measures 2. 25 inches diameter and ~3 inches deep.