I am not impressed with this purchase. My chair is reasonably heavy but no more than I think most office chairs are. The mat is really thin and the wheels have made indentations almost immediately. The mat also travels on the floor so you need to continuously reposition it. The mat is really thin (no more than the thickness of poster card). Really overpriced considering this is more than £30 a piece. I'm not sure how well it is protecting the carpet.