Designed for improved long-range patterning, the Browning Invector-DS Turkey extended choke tube will immediately enhance your shotgun's ability to take down turkey effectively at longer ranges. he Invector-DS concept not only includes a longer tube overall, but the actual constriction of the choke occurs over a longer distance. This longer, more gradual choke taper creates a tight pattern that exhibits greater uniformity and far fewer flyers. The result is extreme tightness at turkey ranges with a level of uniformity that results in more head and neck hits with your shot. Importantly, Invector-DS choke tubes are not rated by the inside diameter as measured by a micrometer, as most competitors do, but measures by the actual tested tightness of the pattern at 40 yards. Invector-DS tubes fit only Browning shotguns designed for Invector-DS and are not for use in shotguns showing Invector-Plus or Standard Invector on the barrels.