The mat will prevent dirt from shoes from getting on your floor. The legs of the chair will indent the mat. However it is a small problem. This mat is sufficient for my computer room.
This said it would be at my home the next day - with free shipping - and it was! That's pretty surprising considering that I live in the extreme boonies... This is perfect to protect the hardwood floors in my home office. It's a nice size too.
The mat wasn't rolled when delivered and had some lumps but it flattened right away. It helps my chair glide while protecting the carpet underneath as I had hoped and looks good.
The add was misleading. First it was not thick enough for high pile carpet.My chair made dents right away that where hard to get out of after just 1 hour. Second the points on the bottom are not long enough. I have to preposition it at least 3 times a day. This mat at best for low profile carpet.