This chair mat says for up to 3/4" carpet. I measured my carpet and it is less than that. The chair mat has dents in it from the chair and does not allow the chair to move freely while sitting in it. I will be replacing this mat.
Arrived in time - bend like hell. Mat is to thin and moves spikes are way to short to have any effect. Chair wheels dent the mat very heavily - makes moving the chair around difficult at times. Does not work well on thicker carpets. Not worth the money.
I think my carpet is a medium pile and I have been using this chair mat for a couple of weeks and it has some pretty serious dimples where the wheels of the chair sit. I make sure the chair is not in exactly the same place on the mat as I believe that would make the dimples worse. I will keep an eye on it and update in the future.