Winter climbing midlayer, standalone at camp, packable warmth for backcountry rest periods – the Cerium is alpine proven. Driven by our obsessive attention to detail, we refined the design, sourced sustainable materials, and kept its exceptional warmth-to-weight ratio. Responsibly-sourced 850 fill down – with Coreloft™ synthetic utilized in areas prone to moisture – provides premium insulation. The outer – recycled 15D Arato™ nylon – is light and durable, a bio-derived liner reduces petroleum use, and an insulated StormHood™ extends protection. As an alternative to down fill insulation, we also offer synthetic fill products, such as the Atom Hoody.