Protect your table from sharp blades, writing instruments and other art and craft tools. These 3mm thick PVC mats feature durable 5-ply construction, a non-slip, anti-glare surface, a 1/2" grid with 1/8" markings for precise alignment, as well as 45 and 60 guides The tough self-healing surface will not break with repeated use and actually extends the life of your knife blades . The green/black mats are reversible with grid markings on each side. Measurements are in inches.