Ultralight 1000-fill grey goose down hoody for low-output alpine activities.The Cerium SL Hoody is a highly packable, exceptionally warm down layer for low-output activities ranging from breakfast at base camp to rest stops on your way to a North Cascades alpine summit. Under its ultralight, abrasion-resistant nylon shell, we’ve placed 1000-fill European grey goose down in the body, arms, and hood for maximum warmth and Coreloft™ synthetic insulation under the arms to help you stay dry when you’re out of your comfort zone but not ready to shed layers yet. Need a heavier option? Try the Cerium Hoody .