Sierra Madre Emergency Sleeping Bag – Ultralight, Waterproof Mylar Thermal Bivy Sack Tent for Hiking, Bug-Out Bags, Survival Kits
Best for
Best ultralight
Amazon rating
Amazon aggregate, one input among many in the Verdict Score
Based on 1 trusted source
Current price
$14.00
Updated May 18, 2026 · 1 min read
Sources behind this verdict
10 reviewers weighted by source trust
The consensus
What reviewers found
Synthesized across the trust-weighted source mix below.
Across the reviewers we read, the Sierra Madre Emergency Sleeping Bag is positioned as the ultralight, lowest-price entry, marketed as a compact mylar bivy that reflects roughly 90% of body heat. Multiple YouTube field reviewers in the data put it through overnight tests, and the manufacturer-side and retailer-side messaging on sierramadreresearch.com and amazon.com consistently emphasize pack size and weight as the main selling points. The trust-weighted picture is more cautious than the marketing.
What reviewers liked
- Lightweight, compact pack size suited to ultralight kits and bug-out bags
- Claimed 90% heat reflectivity in line with category leaders
- Solid Amazon signal (4.6 stars over 560+ reviews)
- Lowest price point among the picks here
Where it falls short
- High-trust r/Ultralight consensus says thin mylar bivies tear easily under repeated use
- Only flagged-tier brand-level reviews (trustpilot.com) were available, discounted to zero per methodology
- No high-trust independent expert review of this exact SKU in the supplied data
- Like all mylar bivies, expect interior condensation overnight
Across the reviewers we read, the Sierra Madre Emergency Sleeping Bag is positioned as the ultralight, lowest-price entry, marketed as a compact mylar bivy that reflects roughly 90% of body heat. Multiple YouTube field reviewers in the data put it through overnight tests, and the manufacturer-side and retailer-side messaging on sierramadreresearch.com and amazon.com consistently emphasize pack size and weight as the main selling points.
The trust-weighted picture is more cautious than the marketing. An r/Ultralight thread tagged high-trust, in a general discussion about mylar sleeping bags, warns that this class of product 'rips too easily' and won't hold up to repeated sleeping. A trustpilot.com listing for sierramadreresearch.com appears in the data tagged flagged, per our methodology that source is discounted to roughly zero and did not influence the score. Net: a reasonable budget ultralight option for an emergency kit, but specialist-community consensus suggests treating it as a single-deployment tool, not a reusable bivy.
- Stay Warm In Any Emergency
- Designed for survival in extreme conditions, Sierra Madre’s thermal bivy sack reflects 90% of body heat, keeping you warmer for longer in cold weather. Ideal for survival kits, bug-out bags, camping, and hiking.
- Waterproof & Windproof Protection
- Mylar was originally designed as a tear-resistant, insulating material by NASA for space exploration. Our durable PET emergency sleeping bag shields you from rain, wind, and snow, ensuring you stay dry and warm no matter the conditions.
- Ultralight With Full Coverage
- Weighing just 6 ounces, this survival bivy sack packs down small, fitting effortlessly into any backpack, glove compartment, or emergency kit for easy portability. Despite its light weight, our bag is larger for full coverage, fitting more body types comfortably.
- Durable & Reusable
- Unlike flimsy emergency space blankets, our survival bag is tough enough for multiple uses. Just fold it up and store it back in the drawstring stuff sack for your next adventure.
- Versatile Use - A Survival Essential
- According to the Red Cross, the elements are the #1 killer in any crisis situation. Whether you're a backpacker, hiker, prepper, or a parent, the Sierra Madre Emergency Sleeping Bag is a must-have—because safety should never be an afterthought.
They'd never hold up to sleeping in repeatedly, they rip too easily. A better quality one like the Space All-Weather Blanket weighs nearly as ...
The bag is elasticated to create structure and hold it close but not touching. One of those over another sleeping bag will boost its warmth ...
Trust tier reflects our editorial assessment of the source, not the individual quote. Hover for the rationale. See how we tier sources →
“Review Sierra Madre Emergency Sleeping Bag – Ultralight ...” · YouTube
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