A heat-reflective bivvy can function by itself as a shelter from cold, wind and rain. However, you can still lose critical heat through conduction (the trasnfer of heat to colder surfaces around you). Thickly pad the area underneath you bivvy with as much dry debris as possible to add insulation between you and the cold ground.

The waterproof, windproof material reflects 90% of body heat while sealed seams keep out rain, wind, and snow. Start a fire with the tinder cord included on the stuff sack. The bright orange is
highly visible, and the rescue whistle signals for help. Use the SOL Emergency Bivvy as a sleeping bag or a blanket to ensure you stay warm until help arrives. 

Features:
Reflects 90% of body heat
Windproof and water resistant
Seam taped