Patternmaster's Code Black Goose tubes will extend out the end of your barrel 1.5 inches and has an effective range out to 70 yards.You will see patterns similar to a full constriction choke on paper with a 2 3/4in or 3in and 3.5in shell, 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. Patternmaster tubes are made of Carpenter Custom 630 (aircraft quality). NOTE: Not for use with ammunition containing flight control wad or slug ammunition. Wad-control technology shortens shot stringProduces tighter, denser patterns Porting reduces recoil