"GBM Series - Green on one side, black on the other, and both sides gridded. Professional quality for all kinds of graphic arts, hobby, craft, shop, and industrial applications, these self-healing and reversible cutting mats are 3mm thick and extra durable. Made from unique composite vinyl material designed for both rotary blades and straight utility blades, they provide a long-lasting, non-glare, surface that can be cut and slashed constantly without showing marks or cutting lines. Can also be used as a desk blotter or general-purpose work mat. Printed grid pattern includes guidelines for 45° and 60° angles and 1/2"" grid lines. Find the perfect center on any project with zero centering lines. All four edges are fully numbered and graduated with 1/8"" hash marks that extend beyond the zero base line for convenience. Mat sizes 24"" x 36"" and above include internal horizontal and vertical graduated hash marks. Non-stick surface is impervious to abrasions and liquid spills. Alvin has been the professional's choice for drafting tools and drawing supplies for over half a century. Since 1950, we have been known for our wide selection of high-quality products at a fair price. Our tools help bridge the gap between ideas and innovations."