if that was directed at me,HS double d but any quality call maker has them. I bought some at the Marysville show and I have also got them at the Eastern Sports show, some of these homemade ones just like predator calls sound great. I also used to get homemade ones from Red Wolfe in New Cumberland before they sold the business, to HS I believe. Red developed the "gobble shaker" which worked great on a bird that needed to be coaxed a few yards more..I have a whole bag full of calls, slates and boxes and diaphragms, etc.. I have used all of them with varying results but it seems when i want to close the deal i end up with double diaphragm to do it. Important thing, if you have time, do some scouting to identify potential victims. DON'T overcall especially if where you hunt is heavily hunted by others. I have killed birds using as little as 2 soft calls, if he feels like suicide that day he will find you!