Palla autoattivante JiuMu con contatore, sviluppo della potenza per l'allenamento di badminton, giroscopio centrifugo da polso

Important Notice: 1. The wrist strength ball is a high-precision product, and users must use it carefully. Any improper use can cause damage to the product and shorten its lifespan. 2. It is prohibited for children under 10 years old and those with insufficient hand strength to use this product. 3. It is prohibited for users to drop the ball from a high place onto the ground or to collide it with hard objects, as this can cause serious damage to the product. 4. It is prohibited to release your grip while the ball is in high-speed motion, or to hand the ball to others while it is in motion, as the resulting vibrations will shorten the product's lifespan. 5. It is prohibited to use any part of the body to try to stop a ball that is in high-speed motion, as this can easily cause injury. 6. Do not add any oily or slippery liquids into the casing, as this will cause the product to become unusable.