With plenty of room for two in an emergency situation, the PIEPS Bivy Bag Alien Double is a fortress. Made from durable Rip-Stop nylon with a heat-reflecting silver coating on the inside, it will keep you and your touring partner warm in even the nastiest weather. Like all PIEPS bivies, the Alien Double can also be used as a rescue sled, poncho, seat-pad, sun sail, rain collector, and a host of other backcountry uses.