There are all sorts of bat speed systems made by "experts" who "work" in all sorts of buzzword jobs. They promote these bats acting as though there is some revolutionary technology in their product. There isn't. The concept is simple; a load up to 20% heavier than your game bat, and a load up to 20% lighter than your game bat. This can be accomplished on your own for less than 5 dollars. Take an old sock and fill it with pennies to equal the desired weight, and tape it to the mid section of a bat. Do the same, and tape it to a lighter youth bat so that it is no more than 20% lighter than your game bat. You just saved yourself several hundred bucks.