Made from 17-4 stainless steel for enhanced durability; 25% larger parallel section for more consistent patterns; Knurled end for quick and easy removal; Constriction laser marked for easy reference; Compatible with multiple shot types including Lead, Steel, Copperplated, Nickel, Hevi-Shot(TM), and Buck Shot; Not recommended for steel shot larger than BB in Full Constriction; Fits various 12-gauge systems including Browning Invector, Mossberg 500, Winchester, Weatherby, and Savage; Backed by Carlson's lifetime warranty for assured quality and performance