The SCR 57 was part of a larger communication system installed on a few aircraft (mostly DH-4's) in the closing months of the war. The transmitter was a larger component and designated as the SCR 68. The setup represents the first model of aviation communication system attempted. Power for the main transmitter was provided by an aerodynamically shaped pod which was fitted under the aircraft. The pod had a small protruding propeller which provided current through a generator. These components were manufactured by Western Electric and they also made the leather flying helmet and components that are show in the paper diagram that is attached to the underside of the lid.
The condition of this example is near perfect, with all internal electrical components intact and unaltered.