18×20 Yellow Heavy Duty Poly Tarp. 6oz. per square yard, 12 Mills thick, 12 x 14 mesh count, 1200 Denier. Heat sealed and rope reinforced edges with grommets every 18 inches. Reinforced Corners. Both sides are UV treated, 3 Ply Material. Please Note: All Yellow Tarps are Approximately 4-6? shorter by length and width than the stated cut size. Other 18×20 Tarps.