I have a rotating self-healing mat and really liked how my blades seemed to cut better on it so went looking for a 4' x 8' self healing for my cutting table. This one has markings on both sides, one side is green, the other side is black. I made my cutting table to fit it as I couldn't find one to fit the table I had at the time. Haven't looked back since and I think my blades last longer on it too. Bought it online but can't remember where as it was a couple years ago.