GrovTec GTSW33 Swivel Set for Most Pumps and Autos Simple modification to magazine cap allows mounting on most pump and autos NOT for use on Ithaca 37, Savage 30, Sears 21 or 30, Stevens pumps, Winchester 1400 or ANY firearm with gas operated recoil Set includes 3/4" wood screw rear stud and one pair GT Locking Swivels One inch swivel loops and all steel construction Black-oxide finish; Made in USA