The Snugpak Bivvi Bag provides protection from the elements year round with its completely waterproof construction. You can carry the bivvi bag on its own for emergencies, use it with a sleep system for wild camping, or with a sleeping bag and air mat for planned camping trips. The Bivvi Bag is made of Paratex Dry fabric, a completely waterproof, durable, lightweight protective shell that is designed to keep out the elements. Paratex Dry is also windproof, which traps heat inside the bag with you to keep you warm and prevents cold air from entering the bag. Take care to not completely seal the Bivvi Bag, because although it is breathable and wicks moisture out of the bag, sufficient air to sustain breathing cannot pass through the fabric. Water vapor from within the bag is transferred chemically to the outside of the bag due to the polyurethane coating to keep you warm and dry. The Bivvi Bag comes with its own stuff sack and packs down to a travel-friendly 5 by 4 inches; weighs only 11 ounces. The water repellent feature of this bag can be maintained by a cool tumble dry after washing and periodic treatment with suitable water repellent products. The Bivvi Bag is 90 inches long and 33 inches wide so that it can fit over your sleeping bag as a protective outer shell. The Bivvi Bag will ensure you are equipped for emergency situations and will remain dry and warm even in the most unexpected weather conditions.