Uncle Mike's 18102 Mag Cap Swivel Set made of Steel with Blued Finish, 1 Loop Size & Quick Detach Style for 12 Gauge Mossberg 500 Includes Two Super Swivels

Uncle Mikes magazine cap swivel set has a factory magazine cap with the swivel base already installed. Just unscrew the factory magazine cap and replace it with the new cap. For the buttstock, a 3/4 inch wood screw swivel base is included, along with two super swivels with Tri-Lock.