I like this size shape and quality of this mat. My only negative is that despite it having little plastic spikes on its underside it shifts position to easily and I keep having to adjust it.
The plastic is a little too soft as my roller chair sinks into the divots made by the legs and it is hard to roll out of them. I expected it to be harder plastic to prevent that.
The wheels of my char sre sinking into the mat and it is hard to move it out of the sunk area. My carpet thickness using the paper clip method is 1/4". I am very unhappy with this purchase.
I wish I could have gotten a matt custom made for thesize of the area I needed it for. I might have preferred one with a lip on the edge to keep my chair from rolling off when I move around. It's taking some getting use to but I think it will serve the purpose of protecting the carpet.
Working great so far. Had to order it on-line but it is much thicker and stronger than the regular ones found in the store which don't hold up on carpet. Time will tell whether this one holds up but it's working great so far.