Redline -20°C

Built for high-altitude mountaineering and deep polar expeditions, this sleeping bag is designed for conditions where sub-zero insulation is a safety requirement rather than a comfort preference. Mountain Equipment sizes it with a roomy expedition profile, deliberately leaving internal volume for drying boot liners or wearing heavy insulated layers to sleep without compressing the down fill. It is a specialized, cold-weather shelter designed specifically for sustained exposure to harsh freeze-thaw cycles.

A rugged, weather-resistant outer shell protects high-loft goose down from the relentless moisture hazards of winter bivies, including frost feathers and tent wall condensation. The interior relies on anatomically shaped trapezoid baffles and box-wall construction, anchoring the down securely over the chest, torso, and footbox to prevent cold spots from migrating plumes. A dense, multi-baffle hood and an expansive magnetic draft collar lock down internal warmth and keep frigid spindrift from seeping inside.

In the field, that high degree of thermal protection demands a realistic concession to weight and pack volume. While top-grade down enables respectable compression for its temperature bracket, this bag will occupy substantial real estate in a multi-day pack. Against lighter, minimalist winter quilts and alpine bags, the durable shell and heavy-duty draft baffles prove their worth through abrasive handling and prolonged survival scenarios. For expeditions where night temperatures reliably drop well below freezing, the thermal headroom is indispensable.