What Our Gearhead(R) Experts Are Saying:"I take the Parsec on trips when the temps drop and I still want to keep my pack weight under control. The 900-fill down lofts fast, the foot pocket is surprisingly effective at warming up, and the zipper doesn't snag when I'm getting in and out with gloves. It feels dialed for real cold."We trust the Parsec 0F Sleeping Bag when cold alpine nights demand warmth that doesn't weigh us down. Therm-a-Rest packs the bag with premium 900-fill hydrophobic down, creating a lofty, compressible insulation layer that holds heat even in damp, early-winter conditions. Zoned construction concentrates insulation where we lose heat most, giving the bag impressive thermal efficiency without unnecessary bulk. Whether we're settling in after long miles or gearing up for predawn starts, the Parsec offers dependable warmth that makes harsh conditions feel more manageable. A down-lined Toe-asis foot pocket helps thaw cold feet quickly, while draft tubes and a cinchable hood seal out frigid air when temps slide well below freezing. Inside, a small stash pocket protects essentials from cold-sensitive battery drain. The YKK anti-snag zipper keeps entries smooth, and the recycled nylon shell and liner provide a soft, durable feel throughout the night. Lightweight enough for long approaches yet warm enough for true winter conditions, the Parsec balances performance and packability for demanding trips.