Stainless steel construction Stainless steel spring Polymer follower Flush baseplate The Auto-OrdnanceA(R) Thompson 1927 (T10) .45 ACP 20-Round Magazine is an aftermarket magazine that is a reliable option for your Thompson replica. This magazine is constructed with durable stainless steel which offers unparalleled strength, lasting corrosion, and shock resistance with a flush metal baseplate for easy handling. Featuring a steel spring with a polymer follower to help ensure smooth feeding and proper cartridge alignment in target and defensive scenarios. 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 its designs. Pick up a new 20-round magazine for your Thompson submachine gun today! Note: Will NOT fit firearms made in West Hurley, NY, or before 1990.