Emergency thermal bivy sacks serve as a last-resort survival supply when things take a turn for the worse. This compact emergency sack is made of the same material as an emergency blanket, but has been constructed to be shaped like a sleeping bag liner. It is constructed from lightweight, heat-reflective material with fully taped seams to protect against wind, rain, and cold.

It is designed to be used as a standalone emergency bag, a sleeping bag liner, or an external waterproof cover to ensure you remain dry and warm in serious situations.

Why We Like It
On multiday rides, I keep an emergency blanket and a cheap poncho in my kit for unexpected bad situations or gear failures. It takes up almost no space, and you can never be too careful!
 
Note: 
Because the material is non-breathable, it creates a total vapor barrier that will trap your body moisture inside. In a survival situation, this condensation can soak your clothing and lead to accelerated heat loss through conduction. This tool is not intended for regular camping or as a comfort upgrade; it is a life-saving device meant to be deployed only when your primary gear fails or when spending the night outdoors is a matter of survival.