If you are over 200 lbs and the chair mat is on a slightly flat carpet you may notice dents in the chair mat. The good part is the dent will go away but it does make it a little difficult to roll a chair back and forth. I bought the same chair mat for my granddaughter and she likes it.
Plastic is not firm enough to support the chair on a carpeted floor! . Creates indintations from the chair wheels causing it hard to move. Don't use this mat on a carpeted floor.