Thompson model 1928 A1 submachine gun, .45 ACP, 10" barrel, box magazine, l.h.s marked 'U.S. MODEL 1928 A1 THOMPSON SUB MACHINE GUN CARBINE 45 AUTOMATIC CARTRIDGE FULL AUTO AND SINGLE SHOT SELECTOR, horizontal forearm with a thin blue finish to metal and good wood, no front sling eyelet or front sight.