1. The base is made of high-quality plastic, which is sturdy and durable. The tennis rubber cord has excellent elasticity. It is beautifully designed and finely crafted, and can be worn at will. 2. The ball is attached to a strong elastic cord with a length of 3.8m, which can be extended to 4 - 8m. It is equipped with a strong, non - slip universal base. It can provide stable support for training because the base has a valve through which sand or water can be introduced to increase the weight. 3. It is easy to use. There is no need to carry the ball during practice. It is lightweight and easy to carry, suitable for individual practice. It is a great gift for friends, family members and children who like playing tennis, and is applicable to many places such as gardens and parks. 4. Product description specifications: Material: Plastic + Rubber; Color: Blue. The tennis trainer allows you to develop tennis skills in the smallest space. You can use it to practice and improve your tennis serve. The ball is attached to a strong elastic cord that can be stretched to 4 - 8 meters, and is equipped with a strong universal non - slip base and a recessed part, which is convenient and practical. This tennis trainer enables you to enhance your tennis skills in the smallest space. 5. The set includes: 1 tennis trainer base and 1 ball with a cord.