Made of heavyweight metal, aluminum alloy shell and steel rotor,It weighs twice as much as plastic.to provide a powerful hand & forearm exerciser which could be equivalent to 50 lbs fitness of other equipment. The metal design is enhances for control, vibration free, and stability.
The wrist 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.