It has a sort of slow roll. It stops if you do not apply force in any direction. I think it is basically a mouse replacement for those with less then fine motor control. I am using it to see if I want to go all out and get a real trackball. Sort of trying it on various games to get a feel for what a trackball would add. Construction is sort of feeble. The ball has a ridge around it and you can feel it when it passes over the rollers.
Bob