Power balls are the latest Worldwide craze, a hand held fast spinning gyroscope about the size of a tennis ball. It explodes with massive force when you activate its internal rotor - there are no batteries.
They combine exercise with fun and are addictive, entertaining and ideal to improve your fitness. Physiotherapists recommend them to tone up your wrists, arms and shoulders - so do sportsmen and some musicians!
The more expensive power balls have a digital counter for you to monitor your score - see if you can exceed a speed of 15,000rpm!
The price difference reflects the quality of the product, particularly the rotor. Millions have been sold.