Allows you to stack two or three balls on the tee at one time by placing a Tee Stacker between each ball. Can be used with a single or double tee. If you swing cleanly on plane through the top ball, the Stacker slides off and the next ball is ready to hit. If you swing off plane by topping the ball, casting, uppercutting, etc, the Stacker is disturbed and the remaining balls will fall. Using Tee Stackers gives you instant feedback on every swing. Tee Stacker drills improve focus and makes hitting from a tee more challenging for all ages and skill levels. Includes two Tee Stackers, two attachment cords with locks, and a mesh carrying bag. Directions and basic drills are included in the package. Batting tee not included.