This is the second pad like this that I've purchased. It is Crystal Clear does not shift has no odor and handles regular domestic cut pile carpeting well. Don't buy the cheaper pads if you have carpet!!! After 12 years my old one is still working great but it is developing spider cracks where the office chair travels over it and the plastic is getting ever so slightly milky in appearance. That is excellent performance in my book. Highly recommended.
I have had problems with the wheels of my office chair sinking into the chair mat. I bought this mat hoping that it would remedy that. It didn't and I immediately returned it. I got one for deep pile carpet. The new one is better but still has the problem.