These 50-round Glock pattern drum magazines are molded from composite/glass-filled polymer. Construction with a clear polymer allowing you to monitor your ammunition. Hardened steel inserts and heat-treated chrome silicon wire springs provide smooth and reliable feeding. The load assist lever provides quick and easy loading. Due to the weight of the loaded magazine they are not designed to be DROP FREE.Disclaimer: Lifetime Warranty VOIDED if customer disassembles magazine! This magazine is not designed to be used with hollow point ammo. For use in Glock patterned pistols.Specifications Weight: 1.5lbs Compatibility: Glock 22 / 23 / 24 / 27 / 35 Caliber: .40 S&W Capacity: 50 Rounds Body Material: Hardened Steel / Polymer Spring Material: High Carbon Steel