Precision Hunter Choke, Full The Precision hunter style chokes are extended, knurled and notched for use with a choke wrench. They are manufactured from high strength 17-4 PH stainless steel with an extremely smooth interior finish. They are suitable for use with steel shot from cylinder through improved modified. All chokes are marked on the head with the degree of choke and on the body with the exit diameter. There is no difference between the Precision Hunter and the Sporting Clay chokes except for the low glare black oxide finish. High quality, low maintenance, known constrictions and a reasonable price! - Fits: American Arms 20ga - Extended - Constriction: .600