●ERGONOMIC DESIGN: The small ring on the side is for hanging band, the concave for tennis ball is very convenient ●Stability: The base has a valve for adding sand and water to increase weight, providing stable support when playing ●LIGHTWEIGHT: The tennis training ball is lightweight and small, easy to use, and convenient to use and store without picking the ball when training ●HIGH QUALITY: The tennis trainer is made of high quality plastic, durable, resilient, suitable for wearing ●GREAT ACCESSORY: Perfect accessory for tennis training to help improve your tennis skills