These mats lay flatter than others I’ve tried from other vendors and returned. I purchased 5 of them for my sewing studio. However 1 of the 5 has a wave that I can’t get out and 1 has a “lip” that I can’t get to lay flat. They also slip around very easily on the hard floor. I’m thinking about anchoring them with double stick tape. I’ve had them a few weeks. Hoping that with use, they will eventually lay completely flat.