These quality replacement Glock pattern magazines are constructed with a hardened steel insert encased in high tech polymer. The polymer coating protects the magazine and prevents deformation, even when dropped. Specifications Weight: 0.2lbs Compatibility: Glock 17 / 17L/ 18/ 19 / 19x / 26 / 34 / 45 Caliber: 9x19mm Capacity: 17 Rounds Body Material: Hardened Steel / Polymer Spring Material: Stainless Steel