Design Features Integrated pad sleeve. Never roll off your pad again No-draft yoke seals around neck to keep cold air from sneaking in 60" YKK #8 zipper on the Stillwater. Mate together any of our left and right zip bags with the same length and size zipper Mummy shape decreases weight & packed size Cotton storage sack & waterproof, roll-top stuff sack included Built in pillow pocket holds a fleece or Big Agnes Pillow No-draft zipper tube insulates along the length of the zipper No-draft wedge insulates the connection between the bag and pad Shell fabric: Fabric is ultra light, waterproof and highly breathable Interior lining: Soft, breathable nylon with stain resistant finish. SeamZero® Patented waterproof, seamless construction Interior fabric loops for sleeping bag liners