Rocky Mountain Hunting Calls Royal Point Elk Diaphragm Call - Built on Rocky Mountain Hunting Calls wildly successful GTP frame, this call is a single latex that is for simply bugling to challenge a herd bull. You can make the absolute most aggressive challenge bugles with it. 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.