I would give it a half star if I could. We just returned it after only 2 1/2 weeks. The chair was digging into it already very thin would not slide. We returned it and bought something else. Quality was poor.
The mat is of a good size so that I can move and not roll off the edge. It's substantial so I can roll smoothly. Only issue would be that the nubbies on the underside have sharp Sharp points and it hurts to pick the darn thing up.