Rocky Mountain Hunting Calls Elk Camp Elk Diaphragm Call - Built on Rocky Mountain Hunting Calls wildly successful GTP frame, this call a single latex that is designed specifically to reproduce a very accurate estrus cry of a cow elk. It will make a mew, chirp or whine. 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.