section class="productDescription"> Temperature Rating ISO Comfort Rating: 48degF / 9degC ISO Limit Rating: 40degF / 4degC ISO Extreme Rating: 15degF / -9degC Materials Insulation: 550FP Duck Down Shell material: 20D 400T Nylon Liner material: 50D 300T Polyester DETAILS & DESIGN The Kelty Pack Cosmic Down 40 is designed with warm 550 fill down and internal stash pocket to store smaller items Equipped with a Quilt-through construction that helps thermal efficiency and a zipper draft tube with anti-snag zipper Features C0 and PFC-free DWR fabrics and natural footbox for more wiggle room Dual slider for ventilation with locking zippers Includes stuff sack