1、Through manual control, the rhythm and speed of ball core rotation can adjusted arbitrarily, the faster speed, the greater the force generated. 2、Life prevent carpal tunnel syndrome, exercise the muscle group of the arm, daily training all the time, relax outdoors at the same time. 3、Built-in automatic elastic equipment, can started easily without any trouble, the power can controlled to increase the entertainment and interest. 4、Long-term using will effectively exercise the arm muscle group, to help fitness enthusiasts arm targeted strength training. 5、Do not need the traditional pull rope, follow the arrowhead to the end, release easy to start, with the rotation of the wrist, feel the centrifugal force produced by the center of the ball, you can keep the wrist ball running. 6、Variable speed color light by your wrist ball with the speed of the ball core, the light will become colorful feeling dazzling rhythm, more fun. Condition: 100% Brand New Item Type: Wrist Exerciser Ball Material: PC + Aluminium Alloy Optional Color: Lighting Green, Lighting White, Colorful Lighting Weight: Approx. 294.3g Size: Approx. 7.7x7.7x7.1cm/3.03x3.03x2.80inch 1 x Self Starting Lighting Wrist Exerciser Ball 1 x Wrist Rope