Packing high levels of warmth within a sleek, lightweight design, the Arc'teryx Men's Nuclei SL Insulated Jacket ensures maximum comfort through cold weather cragging, ice climbing, and mountaineering exploits. The Arato 10 nylon shell is extremely lightweight, enabling easy stashing within the included stuff sack, which conveniently clips to your climbing harness. The shell's DWR treatment repels outside moisture to keep you pleasantly dry through passing snow and rain showers. Higher levels of Coreloft insulation through the body 80 gram ensures fiery warmth where it's needed most, with slightly less 60 gram through the sleeves and side panels to reduce overall bulk. The No Slip Zip closure allows you to unzip a portion of the jacket for better ventilation without the entire portion unzipping during rapid movement. Other key features include an adjustable, helmet compatible hood, insulated, zippered hand pockets, as well as a slim fit with Arc'teryx's Ergonomic 3D patterning for unrestricted movement.