Old mat failed after many years and I saw Staples was open (a necessary store). I purchased mat and put it in place; chair rolls nicely. Mat is good size and does its job.
I purchased this chair mat because like many people I am working from home more and my office chair was destroying my carpet I choose this one for its sloped edges not a hard bump if your chair rolls off of it. The one downside is it is very heavy to move as I discovered when replacing the rug.
I thought carpet chair mats were the same but because it's hard for me to roll on I probably should have ordered an harder mat. I guess it depends on the thickness of the carpet.