This chair mat is thin...very thin. I have it sitting on a thin carpet. Being so thin (and very soft) the chair wheels make dents in the mat. Considering what it is it wasn't cheap. For a couple dollars more I could have purchased a thicker sturdier mat. I would definitely not buy it again. In fairness if placed on a hard floor it would probably be acceptable.
Good mat as far as an El Cheapo goes. However if the carpeting you seek to protect is anything more than standard office "hard and flat" and has even just a little "depth" to it this mat will crater around the chair wheels.
Not sure why staples is insisting that I rate this product. It's a floor mat. Plastic goes over a w to w carpet. Protects from chair wheels. The last one was good for about 3 years.