Arc'teryx Cerium LT Jacket - Men's Worn as a mid layer or standalone piece in cool, dry conditions, the Cerium LT Jacket delivers exceptional warmth for little weight. Premium 850 fill down is resilient, lofty and warm. The Arato(TM) 10 shell provides lightweight durability, and Down Composite Mapping(TM) strategically places Coreloft(TM) synthetic insulation in moisture-prone areas. Articulated construction moves with the body, and sewn-through construction is used to further reduce weight and increase packability. CERIUM Streamlined, minimalist and lightweight technical down insulation. High warmth to weight ratio. LIGHTWEIGHT High performance, minimalist design that is durable for its weight. ARC'TERYX ESSENTIALS Versatile high performance designs for diverse activities and conditions. DOWN INSULATION Highly efficient natural insulation that compacts well and offers excellent warmth to weight.