The Cerium LT hoody is the lightest and warmest peice in Arc'teryx's new range of down jackets. Aimed at backcountry & alpine use - the key to the Cerium's weightless, agile freedom include underarm gussets for better mobility, a three part sleeve construction for better elbow/arm articulation, Down Composite Mapping to protect against moisture and a very lightweight yet durable face fabric that can hold up to everyday wear.
Read more at http://www.ukclimbing.com/gear/news.php?id=5875