Product Size: 7.0 * 7.0 * 7.0 cm Color: platinum colored lights, platinum red lights, platinum blue lights material: plastic Package content: 1*wrist ball 1.THE FUNCTIONAL PRINCIPLE With a concentrated and measured movement of the ball in the hand, the metal rotor can be revved up: The higher the speed, the heavier the hand exerciser becomes due to the forces generated 2.MaterialThe is made of metal and with its heavier weight achieves a higher training effect of up and is particularly suitable for strength athletes and ambitious athletes 3.THE AUTOSTART Place your thumbs on the rotating body and pull the Powerball up to the stop or place the rotating body on a table top and pull the Powerball up like a wind-up car, let go or lift off the table top and start then with circular rotary movements 4.SMALL STRENGTH TRAINING Regular use of the Powerball is a perfect training of the gripping apparatus for athletes who rely on strength in their hands, but also musicians and people who work a lot with a keyboard 5.TRAINING EFFECT The positive effects of training with the Powerball include: Increasing the gripping force of the fingers and coordination skills - Trains shoulders, forearms and upper arms