For sale in good condition, light weight (aluminum, insulated, water tight, outlets, lighting, heater, and more! could be used as a cool camper. Some History This series of RATT RIGS first appeared in Army Documents in 1965 but it appears they were only in development at this time. The NSN number field is even blank in these documents. Also, early pictures in the Signal Reference books look nothing like the final product. It is my opinion from both reference material and my time in the Signal Corps that they came into general use beginning about 1969. These sets are medium-power, general use vehicular radio sets primarily for use in tactical radio teletype operations. The 122 partially replaced the AN/GRC-26(*) and the 142 replaced the AN/GRC-46(*). Because of the range of vehicles they were used with, two shelter types were produced. The S-318 first, mainly for the 3/4 ton trucks, and then the slightly larger S-250. They were mounted on the M-37, M-715, M880 and the M-561 series of vehicles, all with the 100 amp electrical system. They later appeared on the HUMVEE shelter carriers just prior to their obsolescence.