Although Terra Nova are confident that their Waterbloc material will outperform any similar groundsheet fabric their Terra Nova Cosmos Footprint offers some extra protection against sharp objects as well as keeping the tent underside clean Terra Nova groundsheet protectors are sized to fit exactly under the inner tent and attach to the tent pole feet with shockcord loops to keep them in place This ensures the weight penalty is kept to a minimum on lightweight models and expedition tents gain the extra durability they need for the conditions they re used in