SCR-610
The SCR-610 was a Signal Corps Radio used by the U.S. Army during and after World War II, for short range ground communications, it was standardized 29 Sept. 1941, Use. Originally used by the Field Artillery for Liaison officers, forward observers, and intra battery, intra battalion communications, it was also used by the Army Air Forces to connect the mobile components of the SCS-51 Instrument landing system, and control towers. It is a battery operated low-powered FM voice transmitter-receiver equipment operating over the frequency range 27 to 38.9 Mc (27 to 38.9 MHz). it produces 20 Watts  at 6.2 volts and 32 watts at 12.4 volts, range is 5 miles. it has two preset crystal controlled channels, and comes with 120 crystals, it can communicate with SCR-608, SCR-609, SCR-628 (as well as other SCR-610's). SCR-609. The SCR-609 is the same, except that the 609 comes with only a battery pack (CS-79).