It's just a German Abstimmsatz AS-26-B version of the common BC-191-*/BC-375-* Tuning Unit TU-26-B LF/MF 200-500 kHz.
I have read of US-made BC-191-* sets serving as Sender (transmitter) S-191 with cosmetic-only changes in post-war West German civil security and law enforcement forces.
Mike / KK5F