Clear 18×20 Heavy Duty Greenhouse Tarp. Finished size is up to 4″ to 6″ shorter in Length and Width. 14×14 Weave Count, 6 oz per Square Yard, 1200 Denier, Grommets every 36 inches, Reinforced Corners. UV protected both sides, 100% Waterproof, 14 Mil Thickness, 1/4″ x 1/4″ Fiber Reinforced Grid. Mildew Resistant, Tear Resistant, Acid Resistant, Artic Flexiblity. Other 18×20 Tarps.