Patternmaster's CODE BLACK DECOY tubes will extend out the end of your barrel about 3/8 of an inch and has 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. Our DECOY tubes can be used with steel or other non-toxic ammunition as well as lead, and with 2 ¾" 3" and 3 ½" shells. Pick your favorite shot size to use which can range from 8 to BB Non-Toxic/Steel and Lead 8 to 000 Buck. CODE BLACK DECOY tubes only come in a Non-Reflective Bronze color and are not ported but have a knurled end for hand tightening. Patternmaster CODE BLACK tubes are made of Carpenter Custom 630 (aircraft quality) 17-4ph stainless steel, Bronze Titanium coated, and are heat treated to the optimum level for best performance. Note: Testing done by Ballistics Performance has determined that ammunition with velocity of 1550fps and below will achieve the best results with Patternmaster Tubes. Not for use with ammunition containing flight control wad or slug ammunition. Patternmaster's 12ga Remington tubes will interchange with Remington 870 and 1100 (NOT 887); Chas Daly current Pumps and Semi-Autos, and Model 206; Chas Daly O/U made it Turkey; H&R Excell Auto; just to name a few. For more information about your shotgun interchange please see the firearm owner's manual or contact the firearm manufacturer. NOT RECOMMENDED FOR USE WITH REMINGTON MODEL 887 SHOTGUNS!