I found the chair mat on a special on the internet. With the discount it was about $16 I could not believe the price. It was rolled up at will call for me so I didn't inspect it at the store. Unrolling it at home I was very surprised at the quality construction. I would recommend this mat to anyone who spends many hours at their desk.
We have residential grade berber carpet with an upgrade waffle pad beneath. No problem for the plastic grippers to maintain their hold. We placed the 36" x 48" lipped Staples carpet chairmat under a large swivel 5-wheeled computer desk chair in our den and it works extremely well. We also placed the 45" x 53" lipped Staples carpet chairmat kitty-corner under our L-shaped computer desk and the smaller 5-wheeled desk chair that we use with it. Each chairmat provides all the space each of us needs to roll our respective chairs back and forth or swivel from computer desk to regular desk quickly and quietly.