This matt is so soft and flexible the chair sinks into it as if there's no matt at all. I saw it was recommended for short pile carpet and we're on a hardwood floor with industrial carpet so I figured it would be great. DOES NOT make it easier to roll the chair in fact it's worse than the carpet alone. I put it into the store room incase someone else wants it.
Needed a new mat for very thin carpet squares glued over concrete. It works fine. Just enough of the little nubs to grip the carpet. My only issue is that if I sit still for a bit the chair sinks into the mat leaving small depressions. I am a smaller person and the chair is fairly lightweight. It sometimes take a bit to move the chair out of the depressions. I have only had the mat for about a week but the mat does seem to correct itself over a few hours. I am not sure if the results would be the same for a large or heavy person or a heavier chair.