(adsbygoogle = window.adsbygoogle || []).push({}); Got one for my birthday there supposed to tone the muscles in your arms etc. It works by starting the inner ball and theres a protective case around it you hold this and roatate your wrist. There better you are, or the more your practice your able to get the rotor running faster, which puts more strain on your muscles. The mesaure the speed of the rotor in rpm, if you have one post your high scores here

i need to get me one of these

I seen some guy in my school with one. Iv used one before. There hard too do lol