There are four sizes in cutting mats. A1, A2, A3 and A4. This is used for cutting fabrics, paper etc., in activities like quilting and craft. It has an one side measuring grid. What's more... it's self-healing! Which means if there is a cut in the mat it will heal on its own presenting a smooth surface for cutting once more.
This means the blade of your cutter gets a longer life ans your cuts are precise and neat.
Note: Do not apply too much pressure as deep cuts on the mat will not likely heal. Store flat and do not fold.
SDI: One side measurement and usable on one side.
Olfa: Superior quality and both sides have measurements and are useable on both sides. (More helpful for quilting etc.,)