What is the toy that goes up and down on a metal bar?

This toy is a metal bar and there is this thing in the middle that goes up and down. You hold it with your fingers. The thing that is inbetween the metal bar is a magnetic circle. Please help me. I really want to buy one but i don't know what it's called|||wheel-o|||Ah yes, that magnetic space wheel thing is what I think you're referreing to. I've seen them called Wizmo Xt before.