330 grams of genius in goose down, the Arc'teryx Cerium Men's Jacket is light, fluffy, and built to be your new favorite midlayer, whether you’re tucking it under a shell this winter, or stuffing it in a pack for cool summer summits. A recycled 15D Arato™ outer fabric is light, compressible, and durable.. along with being wind and moisture resistant. The inner fabric is an innovation of bio-based fibers (made from castor bean oil). Between them is an 850 fill European white goose down and, thanks to Down Composite Mapping™ strategically places Coreloft™ synthetic insulation where you’re likely to get damp and compromise the down. It is so light, so compressible, so packable and perfect, it comes with its own stuff sack. A tailored fit for gliding under shells make this an ideal piece for layering, the internal zip security pocket.. often left off in an effort to save weight and expense, makes this an ideal travel piece. It’s perfection in a puffy, the perfect layering piece for the man who prefers the warmth of natural down.