I am experiencing depressions in the mat. When I sit down for more than 5 minutes there is a depression. This was supposed to be a mat of 145 mm. thickness and resistant to depressions. It is not. It is also not a $91.00 mat. I expect to be replacing this mat within the year. Do not buy this mat if you are expecting a firm mat resistant to depressions on a medium pile carpet and lasting for 2+ years.
This chair mat is good quality and the right size and lays completely flat. Three absolute reasons that I chose it and I was not disappointed. It was more than I expected to spend but I was willing to pay the price because of the quality that was explained. I would recommend this item.