The Phelps Plastic AMP Pinnacle Series diaphragm calls use a "Tall Dome" that is ideal for people with a tall palate. These calls make authentic bull and cow sounds. 3 calls equipped with 3 different latex thicknesses and stretch options to match your calling preferences. FeaturesPinnacle 1: Light Build = Light Air Pressure Pinnacle 2: Medium Build = Medium Air Pressure Pinnacle 3: Heavy Build = Heavy Air Pressure