Abso­lutely fail-safe and won’t ever open accidentally. The plunger sleeve on the Swiv­eLock screws in to lock, and unscrews to release, the gate. Super Swivels fit any Uncle Mike’s base and interchange with the older QD 115 BL sets. Set includes 2 blued swivels, 1 wood screw mount, 1 machine screw mount and nut.