Welcome to Western Mountaineering Sleeping bags! Simply the best! If your planning a thru hike, doing the JMT or just going hiking, fishing or hunting then the UltraLite is a great choice. When Western Mountaineering says good to 20Adeg they mean it. Compare it next to your friends "20Adeg" bag and you will see the difference. The full down collar helps to seal in heat around your neck without adding excess bulk, and 16 oz. of high lofting down pumps this bag to 5". The total weight of this very compressible package is only 1 lb. 13 oz. Another reason to buy Western Mountaineering: It is a small business like ours, run by people who love the outdoors. Eastside Sports is owned and operated by former(for now) thru hikers. The owners are PCT SOBOs from 2015. Past employees who are still around but now retired hiked the PCT in the 1970s and 1980s. Other employees were former backcountry rangers from several different national parks. Features Full-length #5 YKK Zipper Full Down Collar 5 1/4" Spacing/Continuous Baffles 59"/38" Shoulder/Foot Girth 5" Loft, 20Adeg F 16 oz. Down Fill 1 lb. 13 oz. Total Weight Tech Specs SHAPE SIZE (FT/IN) RATING LOFT (IN) INSIDE GIRTH SHDR/HIP/FOOT (IN) FILL WT. TOTAL WT. STUFF SIZE (IN) MUMMY (W/ FULL COLLAR) 5&';6" 20F 5.5" 59"/51"/38" 15OZ 1LB 12OZ 7"X13" MUMMY (W FULL COLLAR) 6&'; 20F 5.5" 59"/51"/38" 16OZ 1LB 13OZ 7"X13" MUMMY (W/FULL COLLAR) 6&';6" 20F 5.5" 60"/52"/38" 17OZ 1LB 15OZ 7"X13"