The Tennis Trainer Rebound Ball with String is an ideal self-practice tool designed for beginners and kids to improve their tennis skills independently. This portable training equipment allows continuous practice without the need for a partner, enhancing hand-eye coordination and stroke consistency. Simply fill the ball with sand or water for optimal weight and attach it to the string for controlled rebound. Note that the racket is not included. This single-pack trainer is perfect for focused, expert-level practice anytime, anywhere.