Carhartt.com describes this as: "Tundra tested, our down Kalkaska jacket is constructed of tough 4.25-ounce, 100% nylon canvas with a durable water repellent finish. For warmth in winter conditions, it features nylon lining quilted with 550-fill down. To protect against the wind, the front zipper is built with an inner storm flap plus an outer storm flap with a snap closure. The two lower-front pockets with snap closures are insulated for warmth, inner-sleeve rib-knit storm cuffs help seal in body heat, and a drop tail adds coverage. The jacket also includes a left-chest interior security pocket with a media port to the inner garment, allowing users to string headphone wires from media players or smart phones. The main seams are triple-stitched for added strength, Carhartt style."