The Long Wind River contains 1265 of duck down, treated to be water repellent for great performance in challenging conditions. According to the manufacturer, the lowest recommended temperature for sleeping in this bag is -24ºC. It is not an EN or ISO test result, rather the manufacturer's view on a temperature you should be able to sleep in the bag. Marmot's new zipper system makes the bag highly versatile: both sides and the front have zippers reaching down to approx. your waist. This enables staying inside all that loft while making breakfast, for instance. The foot box zipper adjusts foot box width: if the closed position feels claustrophobic, open it up for extra room. - Regular size: suits users up to 183 cm, shoulder girth 162 cm, hip girth 150 cm, foot box girth 124 cm - Main material: ripstop nylon, recycled - Liner material: nylon, recycled - Hood baffles are carefully designed to stay lofty around your head - RDS-certified duck down fill, fillpower 650+ - Stas