Feature: 1. Exercise Arm Strength and Swing: The weight trainer warms up before practice or competition, which is used to warm up and exercise arm strength and swing. 2. Good Functions: Increase the weight of the racket, change the gravity of the racket in seconds, correct the motion, and increase the hitting force and stability. 3. Accelerate Formation of Muscle Memory: Tennis racquet weight adding device can accelerate the formation of muscle memory during swing, and make your muscles stronger. 4. Steel Material: Tennis racket swing weight is made of metal steel material, durable and easy to use, can be screwed on the tennis racket both sides. Increased weight is 100g. 5. Fast Swing Speed: When you finish your workout and remove the tennis racket swing weight practice training aid, you'll get faster swing speed and stability. Specification: Item Type: Tennis Racquet Weight Adding Device Material: Steel Color: Black Increased Weight: Approx. 100g / 3.5oz (±3g / 0.1oz) Product Size: Approx. 39.5x16.5mm / 1.6x0.6in. Package List: 1 x Weight Adding Device