After reading reviews about the medium pile mats I decided to get the high pile version even though my carpet is medium pile. I'm glad I did because this one is nice and heavy lays flat and allows for easy chair movement.
Fits perfectly with my desk and chair. Firm fit — no sliding.Only problem that I have found in the past is that you need to replace the mat every 2-3 years as it wears out. If the manufacturer can solve that problem using better plastics then you have a real winner.
Expeller it to be firmer. Was leaving caster impressions so I put a heavy duty piece of cardboard under it and problem solved. Our carpet/pad is only about 3/4” thick max to.