I ended up buying two chair mats as they are too thin and the wheels on the chair sink into the mats preventing easy rolling. I weigh about 175lbs so didn't think this would be a problem. Using two mats helps but turned out to be a more costly fix than I had imagined.
This mat is made of very soft plastic. The wheels of my chair sink into it and cannot roll without effort. Since the wheels sink into the mat they also sink into the carpet. So what is the purpose of the mat. I will be tossing it in the trash soon and go shopping at a store what a novel idea and not in line.
I really appreciate the fact that Staples online could deliver this product (chair mat) to me because the store does not stock this particular item. Shopping online was easy.