I bought one and a few refills.
Big mistake.....................I should have bought more!!!
My Rufus, who is not at all well and we still have no diagnosis, came to life with this thing. He went totally insane and just had a ball. The others had to wait their turns, which is why I ordered more.
Even my oldest kitty, Miss Rikers, with severe arthritis had an absolute ball with this toy.
Frosty clamped down on this thing and we walked around the whole house with me on the other end. He even growled at me when I tried to take it out of his mouth............nothing menacing.............but he hasn't done that since he was a kitten.
There are others as well which I ordered directly from the website.
Only Natural Pet was where I got the first one with the refills.
My 6 cats

And me................I had a ball playing with them...............
http://www.onlynaturalpet.com/products/Go-Cat-Cat-Catcher/317003.aspxhttp://www.go-cat.com/misc_general_items.html