who loves their power ball?

[Vicious]

My friend has one of these. He said it's supposed to help with your forearms or something. It is basically a gyroscope. It's a ball inside this plastic type of cover. And the goal is to move your wrist in such a motion as to keep the ball spinnning inside the plastic. It does take some practice. But I don't see how it can help your forearms look like Popeyes.