My last 30 years of playing and coaching experience has helped me create this incredible device that I have used now for the last two years while going through research, development and play testing. The results are in and they are incredible. My students are all improving at double to triple the rate with every aspect of their game. you can check it out online: the domain is Sweetspottertennis and you can buy it at indiegogo for 1/2 price for the next two months under Sweet Spotter. Please share, we need the world to play great tennis.