【EASY TO PLAY&CONTROL】You only need to push the core in the direction of the arrow, start by the internal spring, no rope,small and lightweight, easy to take, exercise anytime, anywhere.This new wrist ball is Auto-Start Style,without pull string. 【HIGH QUALITY】The ball built-in spring uses the inertia of the spring to rotate the center of the ball. The device rotates smoothly without noise.The spherical shell is made of special plastic material and is very durable.It is equipped with a high-grade silicone rubber anti-slip ring.It helps the gyro ball not to let go of your hand. 【EYE-CATCHING DESIGN】With the novel design of LED lights, you can see how fast the rotation speed is. When rotating, the LED lights up. The faster the rotation, the brighter the LED light, as long as it rotates, it will remain lit, set sports, fun, fitness in one,The light will only illuminate when your speed is fast enough 【GOOD FOR HEALTH】Exercise your fingers, wrists, hands, forearms, shoulders, increase your arm strength,Restores muscle and joint pain,help reduce the inflammation caused by Arthritis, Carpal Tunnel Syndrome, RSI or Tendonitis. ideal for athletes, guitarists, pianists. 【NO BATTERIES】No battery and any power supply, no electromagnetic radiation,Through human control,Freely adjust the rhythm and intensity of the movement,please CONTACT US if any question, we will give you a 100% satisfied customer service.