Rab Ascent -12C / 10F Sleeping Bag Cold Nights, No Compromises When the temperature drops well below freezing and a good night's sleep is the difference between a strong day and a wrecked one, the Ascent -12C delivers. It's a wide mummy bag built for trekkers and backpackers who need real cold-weather performance without the weight and bulk of a full expedition bag. At its core, L. O. F. T(TM) construction uses alternating wide and narrow baffles with sidewall baffles to keep the down distributed evenly across the bag, so you're not fighting cold spots at 2 a. m. The 650FP duck down is hydrophobically treated and hand-filled in Sheffield, meaning it arrives with full loft intact. A Pertex(R) Quantum outer keeps wind from robbing you of heat. The second shorter zip is a practical touch that lets you free your arms for camp tasks without losing the warmth you've built up. Features650FP European duck down with Grangers fluorocarbon-free hydrophobic finish resists moisture and retains loft in damp conditions L. O. F. T(TM) baffle construction alternating wide and narrow baffles with sidewall baffles eliminate cold spots for consistent warmth through the night20D Pertex(R) Quantum nylon ripstop outer with fluorocarbon-free DWR windproof and weather-resistant without adding bulk ISO comfort rating 23degF / limit 10degF / extreme -27degF wide mummy fit with second shorter zip for arm access at camp | Rab | Ascent -12C / 10F Sleeping Bag | Nylon