I replaced the previous pad because it had cracked in many places under the chair. The new pad seems thinner than the last one so I expect it will fail sooner.
The check out person was very friendly and helpful when I changed my mind halfway through my transaction and purchased this mat rather than the folding one that I had originally.
Chair mat sinks into the carpet further than I thought it would so therefore it makes it difficult to move smoothly over it.... . I will replace it with another kind of chair mat. I would not recommend it for low pile carpet.