Carlson’s Choke Tubes are available for most shotgun models and serve as a perfect replacement to damaged worn out or misplaced factory choke tubes. Carlson’s Choke Tubes are manufactured from corrosion resistant 17-4 PH Stainless Steel they are compatible with steel or lead shot (Steel shot should not be used in any Turkey Choke Tube) and are backed with a lifetime warranty. – Technical Information: – Gauge: 20 – Thread Pattern: Browning Invector Plus – Popular Firearm Models: Browning Gold Winchester Super X and Winchester Supreme – Ported: No – Shot Type: Hevi-Shot lead or copper plated lead – Constriction: Turkey .585 constriction – Material: Stainless Steel