The product description said this product would be fine with pile carpets. It is not stiff enough - so the chair creates dents in the mat. They are not permanent but with a rolling chair you are constantly stuck in the valleys that it creates.
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.