This is an Auto Ordnance factory 10-round magazine for Thompson submachine guns in .45 ACP.
Featuring all-steel construction, including steel internal springs and steel followers, these compact 10-round magazines are ideal for target practice or bench-rest shooting. Founded by John T. Thompson as the company that would go on to launch the historic Thompson submachine gun, Auto Ordnance stays true to the heritage of America’s most iconic weapons while continually refining and improving designs.