This AR-556® QD (Quick Detachable) Receiver End Plate is designed to fit standard MIL-spec lower receivers. Its unique low-profile design allows operation of most collapsible stocks in all positions (including fully collapsed). It accepts any quick detach (QD) sling swivel with 0.37'' diameter swivel stud. The sling swivel housing is designed with quarter-turn rotational over-travel stops to restrict swivel movement and prevent binding against the buffer tube and sling tangling. The plate is made from solid steel with a matte black finish. Quick and simple installation - no modifications required to the firearm. Made by UTG Leapers.