Machined steel magazine extensions increase capacity without gunsmithing or permanent alterations to your Remington 870, 1100 or 11-87 shotgun. Knurled, threaded collar screws onto the end of the mag tube. Includes high-performance, extended length magazine spring and an unbreakable, high-visibility, nylon follower. Loop models features a stationary loop on the left side of the extension to accept direct attachment of tactical-style slings without swivels. QD stud models include a quick-detach, swivel stud mounted either in the center of the magazine cap or at the front of a plate below the extension to accept slings with quick-detach swivels. All models fit 12 gauge only.