The Browning 20 Gauge Invector DS Extended Choke Tube is a choke tube that is long on length and even longer on performance. Each tube extends beyond the end of the barrel for easy removal and for the most even, tight patterns in Browning's history of choke tube design. It features proprietary differential banded gas seal that eliminates residue build up and makes chokes easy to remove and install. Integrated spring suspension hold the seal tight, yet allows expansion against the barrel wall for a perfect fit and smooth transition for shot column entering the choke. Gas is controlled at the interface between the choke and where it seats in the bore. It is available from skeet to full choke and the patterns tighten consistently and reliably.