This fantastic invention is great to keep you burning those calories even when you are sitting down. Try the Wrist Ball & give your forearms & biceps the ultimate workout. The ball-within-a-ball system creates an immense gyroscopic force & it doesnt even require batteries. So lads, get your hands on one of these bad-boys for those occasions where you cant go to the gym. The Wrist Ball is also brilliant for strengthening your muscles for a particular sport or simply just for fun. Just wind up the thread & pull briskly. What's more, this gyroscope is seriously addictive for all ages making it ideal for play, exercise or fun competitions!PERFECT FOR GOLFERS, MUSICIANS, SQUASH, TENNIS, FENCING, BASKETBALL, BADMINTON, ARCHERY, CRICKET etc... OR JUST FOR FUN! Also great for rehabilitation & relief from carpal tunnel syndrome & RSI.