The SE-88/5 was a clandestine 5-Watt short-wave radio transmitter and receiver set developed around 1938 for covert military and intelligence operations.https://www.wftw.nl/267%20SE%2088-5%20v1%2000.pdf
Overview and Design Power Output: Rated at 5 Watts. Configuration: Housed the transmitter (S. 88/5) and the receiver (E 88) in separate distinct metal housing boxes.
Similar devices SE 74/12 & S 90/40: Later portable shortwave transmitter-receiver systems used by clandestine operatives and commando units. SE 109/3 ("Keksdose"): A late-war ultra-compact radio station housed inside a biscuit tin, utilizing low-power battery packs.
See also Amateur radio homebrew List of amateur radio transceivers QRP operation Vintage amateur radio
References
External links The Tenuous Thread of Communication – Spy Radios NAZI SPIES' RADIO SET - British Pathé on YouTube