The Escapist Tarp Groundsheet is made with Tyvek® material. Tyvek is a very tough, waterproof material that sheds mud and water easily. A tarp groundsheet is invaluable for protecting your gear from groundwater, thorns, mud, and dirt. Our Tyvek Groundsheet is sized to fit under either size of the Escapist Tarp shelters and the Escapist Bug Tent and But Net inners.