This 140mm premium magazine fits 1911 double-stack handguns Engineered for those who refuse to compromise between aesthetics and absolute reliability, the Atlas Premium line is the pinnacle for the 1911 double-stack platform. Each magazine is built around our premium stainless-steel tubes, featuring performance geometry to ensure consistent feeding. Now featuring the toolless Alphalock Basepad, these magazines offer efficient maintenance, no matter the location. Expertly anodized in a range of finishes, these basepads offer both the high-end finish and function that Atlas is known for. In combination with the field-hardened magazine springs and injection molded followers these magazines deliver performance in every aspect. Whether you're running a stage or on the range, trust the magazine built by shooters, for shooters. Designed for most modular 1911 double stack style pistols, including Staccato* and Springfield Prodigy. Features: Caliber: 9mm Capacity: 21 Tube: 140mm Follower: Lockback Spring: 18% Overpower Alphalock Basepad: Black Compatibility: All Atlas Gunworks Pistols with a tactical or carry magwell All known 1911 double stack modular pistols with no magwell or a Staccato Compatible Magwell Staccato*: Staccato C2, Staccato P, Staccato XL, Staccato XC using a Staccato Magwell Springfield: Prodigy 5" 1911 DS, Prodigy 4.24" 1911 DS