Layfield's Insulated Tarp, with a layer of nominal 3mm closed cell expanded polyethylene foam, is a water-repellent, lightweight reinforced polyethylene (RPE) outer shell. The perimeter of the tarp contains the entire composite sewn into the material. You can find brass grommets every 20" or 24" to provide a higher density of the ties and strengthen the tarp's overall connection to scaffolding.