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.