How to Choose Sleeping Bags for Backpacking
NEMO Sonic Sleeping Bag
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An ingenious 850-fill-power cold-weather down backpacking bag, the NEMO Sonic 0 has gills that allow you to regulate the internal temperature by as much as 20°F without letting cold drafts inside.
Shop newer versionKey Details
Fill
850-fill-power down
Temperature Rating (F)
0 degrees (F)
- Premium 850-fill-power duck down offers maximum loft and warmth at minimal weight, yet compresses down small
- Stretch construction at the knees helps maintain bag shape, thermal efficiency, and loft, while offering enhanced volume so you can sleep on your side or with your knees bent
- Adjustable Thermo Gills allow regulation of the internal temperature
- Nylon shell has a light waterproof breathable coating on the backside of the fabric and a durable water repellent on the exterior to protect against moisture and condensation
- Waterproof breathable footbox protects down from tent wall condensation and enhances comfort
- Internal draft collar seals in heat and blocks out cold
- Drawstring stuff sack and a cotton storage bag included
- Winner of Backpacker magazine's 2015 Editors' Choice Award
Temperature ratings are intended as a guideline to help you compare products, rather than a guarantee of warmth, since many different factors contribute to your comfort while you sleep. Backpacking bags are typically rated for temperature according to an independent testing protocol—currently International Organization for Standardization (ISO) 23537, though some older items followed European Norm (EN) 13537. Testing is based on a person wearing one base layer and a pair of socks, sleeping on an insulated surface with a minimum R-value of 5.38.
Each bag then gets 2 ratings: the Comfort rating is the lowest temperature at which the bag will keep the average "cold sleeper" comfortable, and the Lower Limit rating is the lowest temperature at which the bag will keep the average "warm sleeper" comfortable. Some brands determine their own temperature rating by aligning to the Comfort rating for women’s bags, to the Lower Limit rating for men’s bags, or somewhere in the middle for nongendered bags.
View all NEMO Backpacking Sleeping BagsEach bag then gets 2 ratings: the Comfort rating is the lowest temperature at which the bag will keep the average "cold sleeper" comfortable, and the Lower Limit rating is the lowest temperature at which the bag will keep the average "warm sleeper" comfortable. Some brands determine their own temperature rating by aligning to the Comfort rating for women’s bags, to the Lower Limit rating for men’s bags, or somewhere in the middle for nongendered bags.
| Best Use | Backpacking |
|---|---|
| Tested Lower Limit | 0.2 degrees (F) - EN |
| Tested Comfort | 13.8 degrees (F) - EN |
| Temperature Rating (F) | 0 degrees (F) |
| Temperature Rating (C) | -18 degrees (C) |
| Shell | 20-denier ripstop nylon |
| Zipper Location | Left |
| Insulation Type | Down |
| Fill | 850-fill-power down |
| Lining | 20-denier ripstop nylon |
| Sleeping Bag Shape | Mummy |
| Compressed Volume | Unavailable |
| Gender | Unisex |
