Interesting Function: Fill the rebounce ball with water or sand, attach it, hit the base attached tennis ball, the elastic rope jumps back. Tennis Training: The rebound ball can train sensitivity, hand-eye coordination and endurance, improve your concentration and training skills, develop interest in sports. Bounce ball: tennis bounce balls are perfect for practicing tennis anywhere. It's very practical. You don't take the ball often. Easy to use: The tennis jump ball measures about 20 * 20 * 7 cm, is comfortable to carry and can be put into your sports backpack. Comfortable training, no need to take the ball, lightweight and portable, very suitable for single player training. PERFECT GIFT: The rebound ball is the best gift for friends who love tennis and kids families. It is suitable for many occasions such as playgrounds, gardens, parks etc. It can help improve the movement of the pitch, foot work and precise tennis control. Product description Specifications: Size: approx. 20 x 20 x 7 cm / 7.9 x 7.9 x 2.8 inches. Weight: approx. 300 g. Packing List: 1 x tennis trainer.