Patternmaster's Code Black Goose tubes will extend out the end of your barrel 1 1/2 inches and has an effective range out to 70 yards. The difference between the Patternmaster Code Black Duck and Patternmaster Code Black Goose is the length the tube sticks out the barrel. (Duck=1" vs. Goose=1 ") The added length is to accommodate a 3 " shell and still achieve a Full pattern. You will see a pattern similar to a Full constriction choke on paper, but because of the patented "stud ring" inside the tube, there is a much shorter shot string. This shorter shot string will allow more shot on target all at once, so your down range energy is sure to kill instead of cripple. All Patternmaster Code Black tubes are crafted of American made, titanium infused 17-4ph stainless steel and are heat treated to the optimum level for best performance. *For best results, Ballistic Performance, LLC, recommends ammunition velocities below 1550fps. Not to be used with Slug ammunition. *NOT FOR USE WITH SLUG AMMUNITION