Designed to go on any barrel the is 7/8" to 1-1/8" O.D; designed to damper out unwanted vibration by shortening the overall settling time of the barrel. Easy-to-install unit simply slips over most standard barrels. Length: 1.68", Diameter: 1.92", Hole diameter: .75", Black in color. Fits Bull Barrels, Muzzleloaders and Scope-Mounted shotguns.