The Phelps Pitch Black AMP Diaphragm Elk Calls feature a newly specified "pitch black" latex and the results are impressive. They are built off of the popular AMP frame and come in a three pack. FeaturesPitch Black 1: Has a looser stretch for easy cow calls and all of the bull vocalizations. Very easy to use and quiet when needed.Pitch Black 2: Has a medium stretch similar to the popular Maverick and Phelps Signature diaphragms. This is a do it all call.Pitch Black 3: Stretched tight for ear piercing location bugles as well as higher pitched cow/calf sounds. The best thing about this call is the life you get out of it.