These quality Glock drum magazines are molded from composite/glass-filled polymer, ensuring reliable feeding and extreme durability. Because of the weight of the loaded magazine, they are not DROP FREE. Featuring all-black, glass-filled polymer construction with hardened steel inserts, these 50-round Glock drum magazines use heat-treated chrome silicon wire springs for maximum reliability and smooth feeding. Finger taps provide quick and easy reloading. Compatible with Glock models 17, 18, 19, 26, 34 and Glock magazine compatible firearms.