Emergency Survival Bivvy Bag

An emergency mylar bivvy bag belongs in every day pack, vehicle emergency kit, and hunting pack because it weighs next to nothing and takes up almost no space — but it's the difference between a bad night in the backcountry and a fatal one if a situation turns serious. The reflective mylar material bounces roughly 90% of body heat back to you, which is how a bag that packs smaller than a paperback book can meaningfully protect against hypothermia in 30°F temperatures.

When and Why an Emergency Bivvy Belongs in Your Pack

Bivvy bags serve a different role than sleeping bags — they're not comfortable overnight gear, they're survival gear. If you twist an ankle on a trail at 4pm in October, the temperature drops 20 degrees before your hiking partner gets back with help, and you're sitting still with wet clothes, an emergency bivvy can be the difference between walking out and getting carried out. At under 4 ounces, there's no reasonable argument for leaving one out of a day pack.

• Reflects approximately 90% of body heat — works in hypothermia-risk conditions
• Weighs under 4 oz — no meaningful weight penalty for always carrying one
• Packs down smaller than a fist — fits in a hip-belt pocket or bottom of a day pack
• Waterproof mylar outer sheds rain and wind for additional protection
• Reusable construction — can be folded back for re-use on a second outing

Buy one and put it in the pack you actually carry on trail. The single most regrettable gear decision you can make in the backcountry is leaving the emergency bivvy in the gear closet because you were optimistic about the weather.