The fishtail parka was first used by the United States Army in 1950 during the Korean War. Following the end of the Second World War the US army recognized the need for a new cold weather combat system, resulting in four main styles of fishtail parka: the EX-48, M-48, M-51 and the M-65. The M stands for model, and the number is the year it was standardized. The EX-48 model was the first prototype or "experimental" precursor to all of them.