Now you can add sling swivels to your favorite pump or auto without altering your shotgun. "Uncle Mike"s" Magazine Cap Swivel Sets have 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" wood screw swivel base is included, along with two Super Swivels. Includes replacement magazine cap with swivel base, 3/4" wood screw buttstock swivel base and two Super Swivels.