Really like the design of it. Never thought the market has such unique wrist ball spinner. And the truth is it really works.AUTO START DESIGN: Compare with the old version need to start with string,our upgraded wrist power ball is auto-start design which is simple to start by rotating the wrist. NEW DESIGN with LED: The gyro ball features a novelty design with LED lights which is fun to see how fast you can get it spinning. Cool LED lights inside will light up while spinning, no battery needed, powered by rotating the wrist. Rehabilitates sore muscles, Kill the time & Add fun! GOOD FOR HEALTH: The power ball can assist body to restore to health. There is a strong reaction at high speed, the faster the speed, the greater the power, and the effect of exercise. At the lower speed, it is also a very effective tool release soothe , recuperate sore and damaged limbs, or help reduce the inflammation caused by Arthritis, Carpal Tunnel Syndrome, Tendonitis. RORATING LONGT TIME: Once the wrist power ball rotating ,it keeps going as long as you keep your wrist moving until you let it stop , no need to worry about it will stop when you exercise . SUITABLE FOR SPORTS TRAINING: Highly beneficial hand grip strengthener for golf, tennis, climbing, cycling, basketball, cricket, martial arts and with improved playing performance for pianists, drummers & guitarists.