Outdoor Research's spacious Advanced Bivy can be used in place of a single tent. It is larger than the Alpine Bivy, with more space for thicker sleeping pads and loftier bags. The patented dual pole system can be used for increased ventilation and interior space, or left behind when weight and pack space are critical. The GORE TEX Respiration Positive fabric allows warm moist air to escape to avoid condensation while providing supreme weather protection. A zippered vent at the base improves airflow on humid nights.