The SMC Safety Lock Carabiner utilizes a double locking mechanism that meets OSHA fall protection requirements. To open the gate, pull the sleeve to the unlocked position, then twist the sleeve and open the gate. Made with the same zinc plated corrosion resistant frame, stainless steel gate and locking sleeve as our popular Large Steel Locking Carabiner. The components in this carabiner were meticulously hand-finished after machining, contributing to the smooth, free gate action that is the hallmark of all SMC carabiners. Additionally, each carabiner is 100 hand inspected for gate action and other functional characteristics before leaving our factory.