The Groundsheet Exogen 1 gives your tent extra protection from wet grounds, thorns, sharp rocks and moisture. It covers the entire base of your tent, including the vestibule. The Groundsheet gets attached to the fly with buckles. For a very light weather protection, the fly sheet can be set up by using the Groundsheet. The Groundsheet is made of a robust 75D polyester with a PU coating on the inside (5000 mm water column).