The Whirl Laser Mouse doesn’t have a roller ball at the bottom, you just glide it but the mouse is flexible. I’m not saying it does gymnastics, I’m saying that it pivots so your wrist can make natural movements and is always comfortable.
It took me a bit to get used to, but now I use it all the time with my laptop. It comes with a tiny USB plug (I’m not sure if that’s the technical name, but that is what I call it) and when it’s not in use I’m not worried about losing it because it stores in the mouse. It’s an extra step with the Whirl Laser Mouse that will save me time in the long run (I won’t be turning the house upside down looking for the plug, when after that it would probably be in the computer or something stupid). I know it will either be in a port or in the mouse.
Here is some more information about Whirl Laser Mouse: