Carry the Thermo Lite Bivvy sack with you on all your outdoor adventures; it provides peace of mind and safety for the day that things did not go exactly as planned. The Thermo Lite Bivvy Sack is an ideal form of protection for any emergency situation. Made with Thermo-Lite Fabric for tough, four ply, waterproof and windproof protection. The fabric has a soft feel, and foot vents to prevent the sac from getting hot and clammy. Packaged in a bright yellow sack for easy visibility.