18' x 20' White & Black Reversible Extra Heavy Duty Tarp Approximate finish size is 17'6" x 19'9" due to hems and seams. 14x14 weave material, approximately 14-15 mil thick. Grommets every 18 inches on all sides, reinforced web loops every 36 inches on the longer sides. Sewn, reinforced corners and a heavy duty 5mm rope in the hem. 6% UV-inhibitor in the HDPE yarn and LDPE coating to extend durability in direct sunlight.