Webbing was a new form of material made from pre shrunk, pre dyed, water proofed, cotton. Designed by a United States Army officer, Captain Mills, it was much tougher than the leather used for all previous military equipment and did not suffer from the unfortunate problem of shrinkage in wet conditions. The .45 Thompson sub machine gun was first manufactured in 1928, the M1 and M1A1 versions appeared in 1942, and ceased production in 1944.