Our highest quality non fire-retardant tarp is designed to withstand the most rugged jobsite conditions. Waterproof and tear resistant, these tarps feature seams that are both heat sealed and sewn for extra strength. Rope in hem plus corner patches add additional strength. The material is significantly heavier than typical blue poly tarps: 4.5 oz. per square yard, with a 12 x 14 weave. Rust proof grommets spaced every 18". For quality and longevity, there is no better tarp on the market.