The Escapist Tarp Groundsheet ismade with Tyvek material.Tyvekis 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 BugTent and But Net inners.