Using hand rotation, spin the internal gyro and challenge yourself and others to achieve the highest number of revolutions per minute.The Strength Ball explodes with mind numbing force when you activate it, giving your muscles a revolutionary workout.Take it in your hand, set the rotor spinning (with the cord provided) and you'll experience an extraordinary sensation. The Strength ball slowly comes alive with gyroscopic force - now start to move your hand and wrist in a circular motion and the rotor inside it begins to spin faster and faster.As the forces on your arm get stronger and stronger, the whirring sound gets louder and louder.At 15,000rpm the Power ball exerts almost 40lbs of pressure on your limbs and is traveling at nearly 250 revolutions per second - no batteries, no motor, just pure gyroscopic power - the fastest human propelled device ever created!What makes this so addictive is the little LCD rev counter on top which tells you how fast you managed to get the Power ball spinning. You can guarantee everyone will want to try to beat it ! Take it from us, it’s seriously addictive… GIFT STATS: Strength BallPower ball measures: Tennis Ball sizedPackaging: Gift Boxed