Patternmaster's Code Black Upland tubes will extend out the end of your barrel about 3/8 of an inch and have an effective range out to 40 yards. You will see a pattern similar to an Improved Cylinder 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. These Upland tubes can be used with Lead, Steel, or other non-toxic ammunition and with 2 ", 3", or 3 " shells. Code Black Decoy, Timber, Pigeon, and Upland all feature a knurled end for added grip when hand tightening. All Patternmaster Code Black tubes are crafted out 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