Weight of user and chair on medium pile carpet causes temporary depressions to form. Maybe that would have been prevented if the mat were thicker? It doesn't move around at all though.
This item was not what I expected. It says it was made for high pile carpet but it's not sturdy enough for that kind of carpet. The chair rollers just sink into the plastic leaving divots. Would not recommend purchasing especially at this price.
The mat met expectations except for numerous black specks in some areas. The specks are inside the vinyl and could not be easily removed. Since the mat lies on top of a tan carpet the specks are not noticeable unless you get close.
I bought this mat because everything else was out of stock. It is thin and the chair legs are almost going through it with only having it for about a month. I definitely would buy something else.