If you have plush carpet or a thick pad this is the mat you should get. I made the mistake of trying a cheaper economy style mat. it does not work. Spend the money - you won't regret it.
It is a nice heavy mat but dents easily and leaves ruts for my chair to roll into. I have to keep moving to a new spot on the mat. The carpet is in fact 3/8 Berber. I am 220 lbs. Probably sending it back.
The size is good but the mat is both thin and slippery. Chairs make indentations so it is hard to shift a chair out of the indentations to ease it forward.
Despite the multiple projections on the bottom th e mat creeps to one side over a few days but does protect the carpet and the rolling chair moves easier