The Naturehike SnowBird Duck Down Mummy Sleeping Bag is the premium cold-weather companion for serious outdoor adventurers. Filled with high-quality duck down and wrapped in a waterproof outer shell, it delivers exceptional warmth-to-weight performance in a mummy cut that locks in body heat from head to toe. Available in three series — SnowBird 2, SnowBird 3, and SnowBird 7 — each with M, L, and XL fill weight options, so you can match your insulation precisely to your conditions. Rated for comfort from 0°C to 5°C, the SnowBird series is built for winter camping, cold-weather backpacking, and high-altitude use where passive insulation needs to perform without compromise. The ultralight construction keeps pack weight low, while the splicing zipper lets you connect two bags for a double configuration when needed. Specifications Specification Detail Brand Naturehike Series SnowBird 2 / SnowBird 3 / SnowBird 7 Style Mummy Filling Duck Down Shell Fabric Waterproof Temperature Rating 0°C to 5°C (comfort) Season Winter / Cold Weather Suitable Height Up to 1.8 m Fill Weight Options M / L / XL (varies by series) Splicing Yes – can be paired with another bag Applicable Users Adults SnowBird Series Guide SnowBird 2: M (510g), L (560g), XL (620g) — entry-level cold-weather performance SnowBird 3: M (650g), L (720g), XL (800g) — mid-range winter insulation SnowBird 7: M (350g / 880g), L (380g / 980g), XL (420g / 1090g) — premium cold-weather performance Why Choose the Naturehike SnowBird? Duck Down Fill: Natural down delivers superior warmth-to-weight performance d to synthetic s — stays lofty and insulating in cold, dry conditions. Three Series, Multiple Fill Weights: Match your insulation precisely to your conditions — no over- or under-packing warmth. Waterproof Shell: Protects the down fill from moisture and ground damp, maintaining insulation performance across wet conditions. Mummy Cut for Maximum Heat Retention: Contoured hood and tapered footbox eliminate cold spots and reduce dead air space. Naturehike Quality: Backed by a globally recognized outdoor brand with a reputation for reliable, well-engineered gear. I For Winter camping and snow camping Cold-weather backpacking and hiking High-altitude trekking and mountaineering Adventurers who prioritize warmth-to-weight performance Campers who want precise fill weight options In the Box 1 × Naturehike SnowBird Duck Down Mummy Sleeping Bag (series & fill weight as selected) 1 × Compression storage bag