I have used three of these chair mats two of which were replacements for the first one I purchased and complained about. Each one of them immediately developed indentations in them from the weight of any object placed on them such as a rolling computer chair in my case. This happens even when the chair is unoccupied. The imprints are not temporary and although they dissipate once the weight is completely removed they never fully resolve. In a short space of time so many impressions accumulate that a rolling chair can no longer roll over the surface of the chairmat with ease which was the purpose I purchased this chairmat to begin with. I strongly recommend against purchasing this chairmat.
I wish I could have gotten a matt custom made for thesize of the area I needed it for. I might have preferred one with a lip on the edge to keep my chair from rolling off when I move around. It's taking some getting use to but I think it will serve the purpose of protecting the carpet.
Working great so far. Had to order it on-line but it is much thicker and stronger than the regular ones found in the store which don't hold up on carpet. Time will tell whether this one holds up but it's working great so far.