​The GMC CCKW is a 2½ ton 6X6 U.S. Army cargo truck that saw service in World War II and the Korean War, often incorrectly referred to as a "Deuce and a Half" or "Jimmy". The CCKW came in many variants, the simplest being open or closed cab, and Long Wheel Base (LWB) or Short Wheel Base (SWB).
Text Taken from Wikipedia