U.S. Art Supply is an industry leader in Art Supplies, so you can purchase our products with confidence. Durable 5-Ply Self Healing Construction 1/2" grid with 1/8" marks for precise alignment as well as 45 and 60 guides. The mats are reversible with grid markings on each side Cutting mats also have lines for cutting diagonals Protect your table top from sharp blades, writing instruments and other art and craft tools.