1. Material: chemical fiber/rubber, etc.
2. Fasten the bungee cord through the thread hole and tie a firm knot
3. Pull out the plug, fill it with water or sand to increase the weight, easy to use
4. There is a tennis groove on the front, and tennis can be placed after training
5. The diameter of the tennis ball is 6.35-6.67 cm, the elastic coefficient is 2.54 meters, and the rebound height is about 1.3 meters when dropped from a hard ground
6. Elastic rope length: 4 meters
7. Weight: 70 grams for the ball, 80 grams for the base

Steps:
1. Base irrigation/sand irrigation
2. Tie the string tennis ball to the base
3. Hit the ball slightly upward to prevent the ball from being pulled back to the ground by the rope