Developed in 1942, the M1A1 is the classic Thompson SMG retooled for faster wartime production. While a number of bells and whistles were deleted for the sake of expediency, the M1A1 retained the Thompson's rock-solid machined steel construction, and was popular with Allied soldiers. While the M3 and M3A1 Grease Gun was intended to displace the Thompson as America's main-line SMG, the M1A1 was the most widely used American sub-machine gun of World War II, and would not be fully out of U.S. service until after Korea and Vietnam. Fixed sights, with the safety and selector switches on the left side of the trigger group, Auto-Ordnance two-line address on the right side of the receiver, Thompson "bullet" logo on top and the three-line military nomenclature on the left, along with "JA" and "GEC" inspector marks and "RIA" and "FK" refurbish stamps. Fitted with a straight forearm, finger grooved pistol grip and a buttstock with a flat steel buttplate. Included with the Thompson is a leather reinforced green canvas carrying case and the book "Thompson Submachine Guns" from U.S. Combat Bookshelf.