Omnigrid Cutting Mat 18"x 24" Green with Grid 1.5mm- This double-sided mat has 18"x 24" area of 1" Yellow grid markings on a Green background. The mat itself is 18.5"x 24.5", 1.5mm thick, and the edges have inches divided into 1/8" markings and precise 30, 45, 60 degree angles.