Mart Cobra 3-Pack Mylar Emergency Sleeping Bags, Reflective Bivy Sacks, 84 x 36 in

Each 84 x 36-inch bivy sack is made from reflective Mylar foil, giving you a lightweight emergency shelter to keep in a backpack, car, or preparedness kit. This set includes three emergency sleeping bags, individually packed for compact storage, with Velcro pouches for carrying and organizing them.

The reflective surface helps reduce body heat loss in an emergency, while the bags are designed to provide a barrier against wind, rain, and snow. Use one for short-term protection when unexpected cold or severe weather interrupts an outdoor trip or leaves you waiting for help.

What to know

These Mylar emergency sleeping bags are intended for emergency use and short-term outdoor protection. The reflective material helps return body heat toward the person inside, the manufacturer states it can help retain up to 90% of body heat. Each bag is waterproof and wind resistant, offering a practical layer of shelter during exposure to rain, snow, or wind. For extended cold-weather camping, use it as an emergency addition to an insulated sleeping bag, not as a replacement for one.

The three-pack makes it easier to place emergency protection in more than one location, such as a hiking pack and a vehicle kit. At 84 x 36 inches, each bag is sized for full-body coverage, and its compact packed format supports storage where a regular sleeping bag would take up more room. What would you want close at hand if a trip takes an unexpected turn? This bivy is designed for exactly that kind of backup use.

Buyers often highlight the compact size, warmth, and usefulness for emergency and car storage. Feedback on durability is mixed, so careful handling is worthwhile when packing and reusing the bags.

How to take care of it

The bags are reusable with careful handling. Before each use, inspect the Mylar for tears, and fold and return it to its pouch gently after use to support compact storage. Keep the pouch with your emergency supplies so the bivy is easy to locate when needed.

Who it’s for

This three-pack suits hikers, campers, backpackers, and anyone organizing emergency supplies for a car, RV, or home. It can serve as a lightweight emergency layer during a sudden cold-weather stop, a power outage, or an outdoor situation where temporary shelter matters. Its role is different from that of a traditional insulated sleeping bag: choose it for compact emergency preparedness and short-term protection, rather than as your primary sleep system for an extended camping trip. It makes sense if you want several individually packed bivies ready to distribute across your gear and emergency kits.

Should you buy it?

Choose the Mart Cobra set when having three compact, reflective emergency bivies is more useful than carrying a single full-size sleep system. The Mylar construction, 84 x 36-inch coverage, and individual pouches make the bags practical for keeping in hiking gear, vehicles, or preparedness kits. For unexpected exposure to cold and weather, they provide an accessible backup layer designed to help retain body heat.