The Nuclei AR Jacket combines seam taped WINDSTOPPER weather protection and warm, resilient Coreloft insulation in a jacket created for cold, wet belays and frigid bivies. The N20mr WINDSTOPPER outer delivers breathable wind protection and sheds falling snow and dripping moisture. Critical seams are taped for more comprehensive weather protection. Light and compressible, effective when wet, and delivering a high level of air permeability to help prevent moisture build up, Coreloft insulation uses crimped polyester fibres that resist packing out even after multiple trips to the stuff stack. The Nuclei is designed with its quilting on the inside. This allows the Coreloft to conform to the body for maximum efficiency. Freedom to perform requires freedom of movement. Arc'teryx selected Coreloft insulation because it delivers its warmth with a low profile. This, along with the functional articulation in the sleeves and gussets under the arms, provides necessary freedom of movement and comfort for long belays. The Nuclei's Athletic fit minimizes fabric bulk but leaves room for a light midlayer. The coated Vislon zipper reduces irritation under a harness by eliminating the need for a storm flap, two zippered hand pockets provide storage and are heavily insulated for warmth, and an internal mesh pocket holds goggles, gloves or toque. A stuff sack is included and can be clipped to harness when not in use. A proper belay parka needs to free the user to execute their responsibility. Visibility is critical. The Nuclei AR's insulated StormHood is helmet compatible and provides full coverage warmth and weather protection. What distinguishes it is its design. The StormHood uses an ergonomic patterning that rotates with the head and employs a three point adjustment that allows exceptional peripheral vision without sacrificing coverage. A visor keeps eyes clear of falling snow and dripping water.