12in x 18in Self-Healing Cutting Mat, Durable self-healing 5-layer construction. Reversible design with a dark background on one side and a light background on the other. Easy-to-use layout with two sets of corresponding numbers for reading left to right or right to left. No more counting backwards! Accurate 1in grid with 1/8in marks for precise alignment as well as 30, 45, 60, and 90 degree guide lines to help the cutting process.