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.Remington 870 Express (with internal mag tube rachet-type system). Includes replacement magazine cap with swivel base, 3/4 wood screw buttstock swivel base and two Super Swivels.