Mountainous Expeditions. The regular-fitting men’s POSITRON is a technical down jacket built for alpine expeditions at 6000m altitudes. It features a warm 800-fill power padding of high-quality European Goose Down. Rab’s down products are ethically sourced, RDS certified, and feature a hydrophobic fluorocarbon-free coating so that they remain dry. The Positron features heat-capturing box-wall construction through the torso, back, and hood. Stitch-through construction secures the sides and arms to increase mobility and comfort. A water-resistant Pertex Endurance face fabric and durable ripstop lining keep the insulation inside this jacket. A sizeable helmet-compatible hood with a face baffle and polymer peak provides warmth for mountaineering activities. Waterproof YKK VISLON AquaGuard zippers fasten the front opening and hand pockets.