The Magnum Quick Detach Super Swivels from Uncle Mikes are as solid a foundation you can find to attach a sling. These QD Super Swivels are designed to take a beating. From shotgun rounds to heavy recoiling rifle rounds, these swivels will hold. Includes special adapter for Beretta 390 magazine cap Adapter also included that works for most pump and auto magazine caps Wood screw base for butt-stock Does not fit Browning 2000, Winchester 1400, Ithaca 37, Savage 30, Sears 21 or Stevens pumps