Sucks...don't buy. Worst I have ever had. This was placed on top of a commercial tight weave carpet...sucks. Chair divited so bad it could not roll. Honestly the carpet was better than the mat. WASTED $$$.
The two chair mats we bought work very well at our two work stations: my home office and my wife's sewing machine cabinet. They enable us to move our older office chairs between desks and work tables - over wall-to-wall carpet.