Designed for high altitude mountaineering and arctic conditions, the contoured mummy design of the Sea to Summit Alpine 2 Down Sleeping Bag delivers efficient insulation, while the updated expedition sizing provides space for extra clothing to be worn inside the bag. The anatomically shaped and oversized footbox can comfortably accommodate boots when necessary. Sea to Summit's Alpine™ Sleeping Bag Series combines their most technical sleeping bag features to deliver reliable performance while cocooning you in the highest quality RDS 850+ Loft Goose ULTRA-DRY Down™. Vertical baffles over the chest section ensure the down insulation cannot migrate or shift to the outside of the bag during sleep, creating cold spots. A side block baffle construction maintains the 60/40 fill ratio, keeping more down on the top of the bag for maximum insulation. ULTRA-DRY Down™ water-repellent treatment protects the down from external moisture and condensation from the inside of the bag, virtually eliminating the negative effects moisture has on down. All Sea to Summit Down Sleeping Bags use Responsible Down Standard (RDS) certified down. The Free-Flow Zip system provides a half zip on the right side of the bag to provide freedom of movement for both arms as well as additional ventilation. The full length, two-way left side zip provides easy access and extra ventilation options. Waterproof and breathable NanoShell™ fabric provides protection from wind and moisture. The tightly sized and carefully panelled hood fits snugly around your head, allowing you to maintain maximum warmth with minimal adjustment. An oversized zipper draft tube is fitted with the lightest and stiffest anti-snag materials for effortless operation and to prevent heat loss through the zipper.  Features  Contoured mummy shape for efficient insulation Expedition sizing for extra space and layered clothing Anatomically shaped and oversized footbox can accommodate boots Free-Flow half right-side zip for freedom of movement and additional ventilation Large internal security pocket Includes lightweight Ultra-Sil™ compression bag and storage cell Sea to Summit Alpine II Ap2 -15°C High Altitude 850 loft Sleeping Bag - Regular Length