From the Imperial War Museums website (IWM UK): Second World War period transceiver set widely used by US, and Allied, Armed Forces in Italy, N W Europe, and the Pacific. The US Signal Corps developed the SCR-536 early in the Second World War, It was produced from 1942 onwards by the Galvin Manufacturing Co. By 1945 130,000 had been produced. The SCR-536 was an extremely popular set and was colloquially known as a "Handie-Talkie". It consisted of a five-valve, low-power, battery operated, AM (HF) transceiver that was designed for portability and ease of operation. It featured a single channel crystal control between 3.5 and 6Mc/s, and it had an R/T communication range of 1 mile over land and 3 miles over salt water. The set was switched into a receiving mode by extending the telescopic aerial, and to transmit the press-to-talk switch was depressed. The aerial was protected by a connected cover. The set was well-engineered and designed and could be held in one hand, hence "Handie-Talkie" . It was used virtually everywhere in the world, weighed only 2kg, and was proofed against fungi and moisture.The SCR-536 was also modified for use in military gliders under the designation SCR-585.Short range portable transceiver. A large green-painted metal box with perforated small round holes in the shape of hexagons (original perforated round black earpiece and mouthpiece missing). On the back is a long green webbing carrying strap. (not original)Between the earpiece and mouthpiece is a plaque that reads "SIGNAL CORPS US ARMY RADIO RECEIVER AND TRANSMITTER BC-611-C. SERIAL NUMBER: 3017. ORDER NUMBER: 1345-WF-43. MADE BY GALVIN MFG CORPORATION CHICAGO ILLINOIS. On label : FREQUENCY 3996 Kev/ CHANNEL/ BAT. DATE Red square stamp walkie talkie, handie talkie, telecommunication, ww2, world war 2, american, wireless equipment, signal corps, us army, transceiver, bc 611 c