Shipped without a box and was folded in half so had to clean and put heavy things on it to flatten it out. But - once that was done the mat works perfectly. Stays in place and is a good size for what I need!
Simply unusable on carpet. Thin and sides move up when sitting in a chair on the mat. As the directions said I let it acclimate to room temperature for 24 hours. I put heavy books on the entire mat for 48 hours to flatten it out. Returned it right after.