Pick up the perfect exerciser for your fingers, wrist and arm to improve your grip and coordination and thus your performance in your favorite sport. Inside Powerball there is a rotor of about 200 gram that is being accelerated by a round movement of your hand. A rotation impulse starts up around the axis building up a stability caused by a moment of inertia as well as the speed of rotation.
By rotating Powerball you will tilt the axis around which the rotor turns and apply torque to the rotor. The rotor reacts with a contrary movement and tries to straighten back up — yet he cannot as it is bound to a guide rail inside the ball. Its only "escape" is to roll "away" within the guide rail. Hence your energy is transformed into an increased speed of rotation.
The rotor can perform as many as 16.000 revolutions per minute and thus generate a force of about 75 times the weight of the rotor: 16 kg!