Filling material : Spanish Down 950G. High spec light weight model -20°C. The Level 8 series is the pinnacle of technology. AURORALIGHT, a lightweight, waterproof and breathable material, is used. Military has a MIL spec, a layering system from level 1 to level 7 for items worn on the body, and NANGA has positioned the sleeping bag as level 8 outer cover layer. The zipper is placed higher than the chest to reduce cold air infiltration from the ground. Double draft tubes are placed behind the zippers to block cold air. Shoulder warmers are placed at the shoulder openings and waist tubes are placed at the nape of the waist. The waist tube is a bulkhead that blocks cold currents inside the sleeping bag and improves warmth retention. Fabric Outer: 10dn recycled nylon silee water-repellent finish, Inner: 10dn recycled nylon silee water-repellent finish. Fill power UDDDX: 90-10% Spanish duck down (770FP), super water-repellent treatment, down volume 950g. Gross weight: 3.4 Pounds. Comfortable operating temperature: lower limit temperature -11? /-20.