Bullet points:Made of high-quality plastic: the tennis balls is covered by wool, very resistant to abrasion, suitable compatible with hard floors (including cement), the entire tennis balls is made of high-quality rubber, low inflation, fast and slow balls velocity, comfortable balls feel, easy to control landing, suitable beginner. The anti-skid pad at the bottom of the training device prevents the training device from moving.Easy to use: The base of the tennis training tool has a valves that can be put in water and sand to increase weight, so you can practice without other operations.Personalized training: Use this tennis review exercise, no need to pick up the balls every time you play. Provide you with stable training support, which is helpful compatible with single practice.Multi-purpose: This tennis swing trainer can help you practice all tennis skills. It is very suitable compatible with indoor and outdoor tennis practice coaches, such as backyard gardens, parks, and does not require a balls machine or walls.The perfect gift: These replacement tennis balls are gifts compatible with kids, friends, and family who like to play tennis. They are suitable compatible with all kinds of people, especially beginners. They can help you improve running movements, precise control of standing and hitting at work, and tennis skills.s:Material: plasticSize: Height: 81cmPackage included:1*Tennis swing trainer