The Olfa folding cutting mat has a durable cutting surface mat and absorbs cuts made by both rotary cutters and art knives. The mat folds flat for easy portability. When flat, the fold line becomes almost invisible. Wavy fold line creates a smooth gapless surface when laid flat. It won't skip threads when cutting directly over fold. Mat has padded non slip backing. It is 2.5mm thick. When mat is open, it is 12.75" x 18". When mat is folded, it is 12.75" x 9.125".