An expedition-grade mummy bag rated to -20F (-29C), filled with 850+ fillpower RDS-certified goose down treated with a non-PFAS Ultra-Dry Down finish. Modified Free-Flow Zip system allows ventilation in warmer hours. Recycled 20D nylon shell with non-PFAS DWR. Mummy cut leaves space for winter layering. Built for high-altitude expeditions, winter alpine trips, and cold-latitude basecamps.
Sea to Summit
Alpine Down Sleeping Bag
Shipping
$934
1 retailer
At a glance6 specs
fit
Expedition mummy
fill
RDS-certified non-PFAS Ultra-Dry goose down
shell
20D recycled nylon with non-PFAS DWR
temp rating c
-29
temp rating f
-20
fill power plus
850
Where to buy
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Description
Last reviewed May 16, 2026
Full specifications
6 fields
| fit | Expedition mummy |
|---|---|
| fill | RDS-certified non-PFAS Ultra-Dry goose down |
| shell | 20D recycled nylon with non-PFAS DWR |
| temp rating c | -29 |
| temp rating f | -20 |
| fill power plus | 850 |
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