My carpet is normal pile not too high not too low. The plactic prongs on the underside of the mat do not hold it in place. Everytime I move in my chair (it has wheels) the mat moves as well until it it bunched up against the edges of the desk which keep it from moving any further. I have to remove the chair and straighten the mat a couple of times a day and the fairly thick plastic material retains the rolling bunches unless you apply heat with a hair dryer to warm it into submission so it will lay flat again. Not satisfied at all.
Bought two of these mats to put under desk chairs and over a newly refinished wood floor. They do the job chairs roll easily they lie flat and floors are protected. I wish they were a little more transparent to let the lovely floor color show through more...but otherwise I am pleased with them.