One of 11 components in the Interchangeable Shotgun System Strengthens connection of the mag extension to barrel. May also be used to mount 1 inch diameter flashlights or lasers to barrel. Includes sling swivel stud which is reversible for right or left-handed shooters. Injection molded from indestructible, black, glass-filled nylon. Made in USA. Mfg Lifetime Warranty. Patent Pending. Clamps to most 12GA barrels as a light mount or clamps on Mag Extensions for Remington or Winchester.