World War II-era Type 31/1 'Sweetheart' clandestine radio receiver, developed for use by the British Special Operations Executive (SOE). A large number of these units were manufactured by Hale Electric Co. Ltd in London to be dropped over occupied Europe, where members of the resistance could use them to listen to coded messages broadcast by the BBC. This unit was designed for use in Norway, where many radios were dropped. The brass operating instructions plate on the front of the receiver is in Norwegian, and the serial number plate on the bottom reads "No. 10589." Knobs on the bottom are the reaction control and frequency adjustment. Includes its battery box, which allowed use of a standard 4.5V flashlight battery (to provide 50 hours of runtime) or a 30V hearing aid battery (which could last an impressive 200 hours). The receiver covers a frequency range from 6 to 12 MHz in a single band. The small size of the radio—the receiver measures 4.5″ x 5.25″ x 1″, and the battery pack measures 4″ x 3″ x 1″—along with its slim design, allowed to to easily be concealed in a coat pocket. In very good to fine condition. World-War II historians and collectors consider these radios to be important components of the resistance movements against the Nazis
