AEG "b2" audio tape recorder

AEG’s sound recorder B, a military version of the AEG K4 tape recorder, was designed for the German Wehrmacht. During the Second World War, the tone recorder B was used for radio intelligence by the German Radio Monitoring Service to record enemy radio communications. For use at the front, the device comprised of 3 portable metal boxes: drive L, amplifier V, and supplies box Z, with a total weight of around 165 pounds (75 kg).