High water-resistance, durable fabric build, high-quality seams, stitching, and zipper make this a sturdy choice. Olive drab green, so it blends in with the environment. Resists punctures and tears and reflects back 70% of body heat.

Cons

Is a bit tight and small; may not be ideal for taller users.

Best Bang for the Buck

Esky

Emergency Sleeping Bag

Most Comprehensive

Much more than just a standard bivy sack, this comes with extra perks.

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Most Comprehensive

Bottom Line

Much more than just a standard bivy sack, this comes with extra perks.

Pros

Lightweight and waterproof, this bivy sack retains heat well and includes a compass and whistle for additional survival support. Sealed seams and tear-resistant coating keep you dry and warm in emergency situations.

Cons

Compass may not be incredibly accurate.

Leberna

Emergency Survival Mylar Thermal Sleeping Bag

Bargain Pick

A good, effective choice, this set of 2 bivy sacks is also an inexpensive option.

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Bargain Pick

Bottom Line

A good, effective choice, this set of 2 bivy sacks is also an inexpensive option.

Pros

Available in a 2-pack; each bivy sack comes with its own carry bag. Constructed of durable, double-sided Mylar material, which is waterproof and windproof. Reflects back 90% of body heat and packs up small and light.

Cons

There are no zippers or cushioning with these.

Go Time Gear

Emergency Thermal Sleeping Bag

Feature-Packed

A rugged, mid-priced option that is big enough for larger user and comes with extras such as an emergency whistle.

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Feature-Packed

Bottom Line

A rugged, mid-priced option that is big enough for larger user and comes with extras such as an emergency whistle.

Pros

Comes with a nylon sack for storage, a 120-decible emergency whistle, and a 550-pound nylon-core drawstring. Ultra-lightweight and compact. Its 26um Mylar resists tears and punctures while reflecting 90% of body heat back to you.

Cons

Bag isn't very breathable, allowing condensation to form on the inside.

Survival Frog

Emergency Survival Compact Sleeping Bag

Durable & Rugged

Works very well to preserve your body heat in an emergency, as well as guard against wind and water.

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Durable & Rugged

Bottom Line

Works very well to preserve your body heat in an emergency, as well as guard against wind and water.

Pros

Available in Safety Orange or Tactical Green, the material is an ultra-lightweight, reflective polyester film that reflects 90% of your heat back to you. Tear-resistant, as well as windproof and waterproof with reinforced, taped seams.

Cons

Some reports that the material here is very thin and rips easily.

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First Reviewed

December 01, 2021

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Written by Melinda Harris

Updated November 2023

A bivy or bivouac sack is a sleeping bag with waterproof, windproof nylon covering. It can keep moisture and cold out even in snowy weather. It’s useful to hikers and climbers and for survival during natural disasters. Bivy sacks are made to withstand rough weather conditions, though some are more durable for repetitive use while others are suitable only for emergency situations. Bivy sacks tend to pack up small and weigh little for easy transport over long distances. All help keep your body heat in with some having body-heat reflection ratings between 70% and 90%. Not all bivy sacks can accommodate tall or large body sizes. Some come with extra survival tools like a compass or emergency whistle.

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