The ARC-5 series of "Command" receivers and transmitters were used on airplanes in the WWII era and later. Manufacturer is the Aircraft Radio Corporation. Made for the Navy, the frequency coverage on this model (520 to 1500 KHz) is relatively rare. The coverage fills in the gap in other military receivers of the day such as the BC-348 or BC-312. This particular set had been converted to 115 VAC operation with power transformer and rectifier tube replacing the original dynamotor on the back. The knobs are not original. Original operation of ARC-5 equipment was by using mechanical cabling similar to automobile speedometer cabling from a control head in the cockpit. This dial scale is very accurate and the set is quite sensitive making this example excellent for AM Broadcast band reception. Much surplus ARC-5 equipment was modified extensively for ham radio use in the 1950's and 60's.