It was created by NASA a few years ago and served as a trainer for astronauts in space. Now it is the reason of the new world competition, a good gift idea and a great fun maker. Once you try it, you will never want to stop, it becomes a kind of drug (since I brought this miracle home, there has not been a day, when my boyfriend did not murmured with it). But fortunately this addiction is totally healthy: it strengths the fingers, hands, wrists, arms and shoulders. As a pianist, and a badminton player, I find it a perfect trainer. Full story