These are made by KCI and a quality replacement or additional magazine for a Glock chambered in 9mm. This magazine will work in all Glock double stack 9mm pistols such as the
17, 19, 19x, 26, 34, and 45. Glock magazines have a hardened steel insert which is encased in a high tech polymer (which is fully metal lined). The polymer coating protects the gun magazine and prevents deformation, even when dropped from great heights.