Offers patterns like a full constriction choke
Stud ring creates a shorter shot string
Helps increase energy downrange
Non-reflective bronze titanium coating
Patternmaster's Code Black Duck Choke Tube will extend the end of your barrel 1" and has an effective range out to 60 yards. Offers patterns similar to a full constriction choke on paper with a 2-1/2" or 3" shell and a modified choke with a 3-1/2" shell. Patented "stud ring" inside the tube creates a much shorter shot string, putting more shot on target all at once for high downrange energy. Works with steel or other non-toxic ammunition as well as lead. Pick your favorite shot size from 8 to 000. Ported design with non-reflective bronze titanium coating. Made of Carpenter Custom 630 aircraft quality 17-4ph stainless steel and are heat treated for amazing durability.