A revolution in choke design. The double seal keeps tubes cleaner. Longer choke tapers are optimized to percentages, not dimension only. Choose from a full selection of constrictions. 12 gauge Invector-DS tubes are for guns listing Invector-DS on the barrels. The next generation choke tube. Fit flush with the end of the barrel but are longer than competitors' tubes. Proprietary differential banded gas seal eliminates residue build up and makes chokes easy to remove and install. Features: Integrated spring suspension holds the seal tight, yet allows expansion against the barrel wall for a perfect fit and a smooth transition for the shot column entering the choke Gas is controlled at the interface between choke and where it seats in the bore From skeet to full choke, patterns tighten consistently and reliably Standard tubes fit flush with the end of the barrel but are longer than competitors' tubes Proprietary differential banded brass gas seal eliminates residue buildup and makes chokes easy to remove and install