Rocky Mountain Hunting Calls Tines Up Steve Chappell Signature Series Elk Diaphragm - Built on the wildly successful GTP frame, this is a double latex call with a special notch cut in the latex so that it can produce an extra excitement in your cow calls. It also helps to make aggressive bugles. The "Palate Plate" elk diaphragm call is designed to be placed further forward in your mouth, behind your front teeth, this helps to prevent gagging and gives you easier control of the latex. To operate the call, place the "Palate Plate" upwards to the roof of your mouth, latex down and open end of the diaphragm towards the front of your mouth.