GLOCK OEM Magazine, 45ACP, 10 Rounds, Fits GLOCK 30, Finger Rest, Cardboard Style Packaging, Polymer, Black 3010 Each GLOCK magazine is constructed from a hardened steel insert encased in high tech polymer to protect the magazine and prevent deformation" even when dropped from a great height. The high quality spring and follower ensure reliable feeding from the first to the last shot.