The Hightail down sleeping bag from North Face has been a dream come true for my winter hiking adventures. The bag is lightweight (important during winter climbs when gear weight can be excessive), goose-down filled (850+ Eastern European goose down fill; the lightest, most efficient down on the market), zippered foot access, rated to 15F (comfortable at this temperature), and extremely packable.
North Face has perfected the Trapezoidal Baffling system to lock the down fill in place and ensure cold spots stay warm.
“Expedition bags utilize two special structural configuration to ensure maximum warmth and comfort. First, the bags employ a special trapezoidal baffle system where adjacent trapezoid-shaped baffles are positioned so that their parallel sides are opposite one another. This configuration ensures a constant baffle volume, keeping down in place and preventing cold spots. Second, Expedition bags add a special box baffle in areas especially vulnerable to cold-the sides of the baf in the core torso area and footbox. These added baffles provide additional loft, ensure vital down stays out, and, consequently, offer added warmth.”