Weighing a scant 170 grams and packing smaller than a grapefruit, the Cerium Vest performs as a minimalist’s alpine midlayer or standalone in cool, dry conditions. Responsibly-sourced 850 fill down – with Coreloft synthetic utilized in areas prone to moisture – provides premium insulation. A bio-derived liner reduces petroleum use, and the recycled 15D Arato nylon outer is light and durable. Streamlined in its design, it layers comfortably under a shell and easily fits into its included stuff sack for compact transport.The Cerium Vest was previously the Cerium LT Vest.