I was a little concerned that it would not hold up to being placed on a low pile carpet but it worked very well. My chair has four casters and I weigh approximately 175 pounds and because the vinyl is thick enough it does not appear to pose any problems punching through and making any holes.
I agree with the other reviewers - after a week there are already indentations from the chair. Okay for my purposes but if you are going to be at your desk for 8 hrs. a day giving this a lot of wear and tear you probably would want to upgrade to a more sturdy mat.
Mat works just fine. Surprised and concerned about the delivery. Found it leaning on the front porch wall with out any protection or boxing. The flexibility of the item and the weather conditions could have been disastrous for the mat or adjacent porch furniture or wall surfaces. The bottom of these mats with the dozens of sharp teeth can cause damage and also made it difficult to handle to bring into the house.