Fits all Remington 12 gauge; Choke systems; Made from 17-4 stainless steel and precision machined; Feature a 25% larger parallel section in the choke thus throwing more consistent patterns than conventional choke tubes; Each choke tube is knurled on the end to allow for quick and easy removal; Each choke tube has the constriction laser marked on the end for easy reference; Lead shot, Steel Shot, Copperplated Shot, Nickel Shot, Hevi-Shotshells, and Buck Shot can be used in Carlsons's Sporting Clay Choke Tubes; Steel shot larger than BB should not be used in any Sporting Clays Choke Tube tighter than Full Constriction; Carlsons lifetime warranty