Feature 1It is made of plastic and rubber, durable and wearable. 2Measures 8.3 inches wide and 2.0 inches high. Fits easily in a tennis bag. 3A great device to practice your strokes, develop a faster swing speed, or simply warm up. 4Very light when empty so it can be stored and carried easily. 5Great teaching tool for beginners and intermediate players.SpecificationOverview: This is the perfect portable tennis training aid. Simply hit the ball and it comes back to you! Fill the basewith water and it instantly becomes heavy enough to hold the unit in place. It is made of plastic and rubber, durable and wearable. Great teaching tool for beginners and intermediate players, Your best choice! Features: 1. The base is made of plastic, durable and wearable. 2. The ball is made of imported natural rubber.Strong and durable. 3. A great device to practice your strokes, develop a faster swing speed, or simply warm up. 4. Very light when empty so it can be stored and carried easily. 5. Great teaching tool for beginners and intermediate players. 6. Measures 8.3 inches wide and 2.0 inches high. Fits easily in a tennis bag. Specifications: Item: Tennis Trainer Material: Plastic and Rubber Color: Blue Base Size: Approx. 21 * 21 * 5 cm / 8.3 * 8.3 * 2.0 in Line Length: Approx. 270 cm / 8.9 ft Weight: Approx. 193 g / 6.8 oz Package list: 1 x Base 1 x Tennis Ball with Black Rope