This is a WWII military MD-7/ARC-5 & DY-8/ARC-5 modulator with power supply for the ARC-5 transmitters.

The modulator has two 1625 tubes and a VR150-30 tube and a 1205-GT tube. It has jacks for connecting a key and a microphone and 5 cable connections. It is protected by four fuses. It is rated at 28 volts DC. It is model # 74912 (TN-40-45).

The dynamotor is model 5DY83AB12. It was manufactured by Stromberg-Carlson and is rated at 500 volts, .25 amps intermittent and at 500 volts, .10 amps continuous.

The power supply is model # 20124.