As soon as I put my desk chair (5 point ball casters) on the mat divots were created. I could not easily move the chair. I didn't even sit in the chair yet! This does NOT work for medium to high pile carpet at all. The advertised use is completely bogus.
Great value. Makes sitting at my home office desk easier to move around than just rolling my chair on my carpet. I need to get another one for my craft area table.