Poly tarps are waterproof covers used to protect machinery, homes, hay etc. from water and dust exposure. Poly tarps are also ideal for covering building materials, firewood and as temporary roof covers and camping. Large size poly tarps can be used as covers on ice skating rinks, athletic fields and go-cart arenas. Poly tarps are plastic coated and impermeable to water. Blue Poly tarps are the most popular kind. They are distinctive in appearance, easily recognizable and the most widely used. Finished poly tarps have their edges hemmed in with metallic grommets punched through. A ball bungee or rubber bungee can be run through the grommets to hold down the cover.