The vinyl chair mat does the job but even after short term use you can see depressions forming. It will not last beyond a few years but if that is good enough for most people then it is fine. It does work well in allowing my chair to move over a carpeted floor.
This Staples Model #: STP-17436 which was in stock at my local store and was supposed to work with an 1/8" flat pile rug but was too thin and chair would not roll. Returned and purchased model 20229-CC designed for a 3/8" flat pile rug which works just fine. I have three of these.