Carlson's Invector tubes are manufactured from 17-4 heat treated stainless steel to withstand heavy buffered turkey shotshells. These choke tubes produce extra tight patterns with copper plated and buffered lead turkey shotshells. The Extended Turkey Chokes extend approximately 1" from the end of the barrel. We have found the .665 Extended Turkey Choke Tube to produce the most consistent patterns with turkey loads. Card shooters try the .655 constriction. Our Extended Turkey Choke Tubes feature a 1.050" parallel section to produce the optimum pattern with your shotgun.