I wasted my money. I wish I could return it. I had a similar one for 20 years. Replacing it with this one is misery. This one crawls up my desk from carpet movement. The other did not move at all. The rollers on my chair quickly creates deep dips where they sit. My prior similar one took an hour to get small dips. This is crawling up my desk as it moves creates bulges instead of laying level and makes it impossible to roll my chair out of the dips.