NEMO Sonic Down Mummy Sleeping Bag
- -20°F to 40°F usable range per NEMO
- 800 FP hydrophobic down, RDS certified
- Up to 72 inches user height
- 1.76 kg, mummy shape
- 77.95 x 31.5 inches L x W
- Thermo Gill vents with multistage zipper
- 100% recycled shell and liner, bluesign approved
- Lifetime warranty against defects
Updated 20 days ago · Based on the Amazon listing and published specifications, not hands-on testing.
A cold weather down mummy for mountaineers and winter campers who want one bag across a wide temperature span. Its winter build adds bulk to a summer pack, and it fits only users within the listed height.
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ASIN: B09RN9L16WCategory: Sleeping Bags
Overview
Not a light summer backpacking bag, the NEMO Sonic is a down mummy built for big mountain cold, with zippered Thermo Gill vents that release heat on milder nights. Chevron baffles hold the down in place, and a waterproof breathable footbox guards against tent wall condensation.
Venting makes the difference: the Thermo Gills and multistage zipper widen the comfortable range, so one bag can cover deep winter and cool shoulder season nights. The listing gives no separate comfort and lower limit ratings, and the shell material field contradicts the nylon fabric listed elsewhere.
Who it's for
Winter trekkers and big mountain climbers sleeping in tents with condensation get a vented bag with a protected footbox. Side sleepers wanting a roomy rectangular cut, or taller users, should look at a long or wide model.
Pros and cons
- Vents extend the usable temperature range
- Chevron baffles stop down migration
- Waterproof breathable Toester footbox
- Hydrophobic, RDS certified down
- Comfort and limit ratings not listed separately
- Too warm and heavy for summer trips
- Single standard size in this listing
- Shell material field conflicts with nylon
Performance notes
Warmth comes from down loft, and the chevron baffles stop the fill from shifting into cold spots. The Thermo Gill vents release heat without opening the main zipper, which is how the bag covers milder nights. Hydrophobic down and the waterproof footbox slow the condensation moisture that collapses loft.
Specifications
| Brand | NEMO Equipment |
|---|---|
| Dimensions & fit | |
| Maximum Height Recommendation | 72 inches |
| Size | Standard |
| Item weight | 3.88 pounds |
| Item Dimensions L x W | 78 × 31.5 inches |
| Capacity & performance | |
| Temperature Rating | -20 °F |
| Construction & materials | |
| Fill Material Type | Down, 800 FP Hydrophobic, RDS Certified |
| Color | Goodnight Gray / Torch |
| Warranty & support | |
| Warranty Description | Lifetime |
| Other details | |
| Occupancy | 1 Person |
| Shape | Mummy |
| Closure Type | Zipper |
| Seasons | Winter |
Frequently asked questions
What comes with the NEMO Sonic sleeping bag?
The listing does not name any included components beyond the bag. No stuff sack or storage sack is listed, so confirm with NEMO if you need one.
Is the NEMO Sonic a summer camping bag?
No. It is built for extreme cold and mountaineering. The vents widen its range, but its winter design runs warm for hot nights.
How do the Thermo Gills on the NEMO Sonic work?
They are zippered vents with a multistage zipper system that you open from inside the bag to release heat and fine tune comfort.
Is the NEMO Sonic footbox waterproof?
Yes. The Toester footbox is waterproof and breathable, shielding the down from tent wall condensation, and it can dry damp clothes inside it.