Sierra Designs' lightest 15-degree sleeping bag ever -- perfect for the backpacker who counts every ounce but doesn't want to give up a good nights rest on the trail. *Patented vertical baffle construction reduces weight while still retaining warmth. *Lightweight, horizontal chambers keeps down in place. *Ultralight Jacket Hood(tm) reduces the weight of the bag while still keeping the warmth by providing a fitted hood for better insulation and decreased heat loss. *Keeps cold air out by utilizing a draft collar with draw cord and zipper draft tube. *Ergonomically shaped foot box allows for ease of movement, while remaining thermally efficient. *Easy access, ventable, snag-free 40" zipper. *Includes stuff sack and storage sack. Zipper Side: Left Fill Weight: Regular: 18oz Long: 20oz Stuff Size: Regular: 6' x 16" Long: 7" x 17" Shell Material: 10D Nylon Ripstop Liner Material: 10D Nylon Ripstop EN Tested: At the most basic level, the EN (European Norm) Test helps Sierra Designs' understand how much insulation is required to keep a person warm and comfortable through the night. The EN Test enables Sierra Designs to confirm what temperature an average man will sleep comfortably and what temperature a woman will sleep comfortably in the tested bags. The two temperature ratings listed on the tags are "Comfort" and "Lower Limit." "Comfort" is defined as the temperature that a standard man (176lbs / 80kg) or, in the case of a women's specific bag, a standard woman (132lbs / 60kg) will be comfortable at. Ratings are based on the user wearing long underwear, socks and a hat, and sleeping on a 1" thick pad.