The Cerium is a success for practically any alpine company. We've refined the design and used more sustainable materials, while maintaining its exceptional warmth-to-weight ratio and compressibility Responsibly sourced 850 fill down fill, with Coreloft™ hollow fiber in areas most prone to getting wet, provides insulation supreme. The Arato™ 15D shell fabric is recycled, lightweight, durable, and colored by mass-dyed yarns. A padded StormHood™ hood adds warmth, and its clean, ergonomic cut makes it easy to layer with other layers.