Mouth Calling 101 is part of the H.S. Strut University Series. It comes with the Premium Flex Diaphragm 3 Pack, which includes three popular H.S. Strut calls. Lure them in with the Double D, Raspy Old Hen and E-Z Rasp calls you will learn to use by watching the 30-minute instructional DVD. If you have ever wanted to master the art of the diaphragm call, this is the combo for you!