Two years ago, Arc'teryx gave lead designer Carl Moriarty a dream mandate: Build the best mountaineering jacket in the world, cost be damned. It needed to be warm enough for nasty conditions, so he stuffed it with the company's top-of-the-line ThermaTek insulation, which, in addition to being more hydrophobic than other synthetics, also boasts a better warmth-to-weight ratio. He then wrapped it in the toughest Gore-Tex material, Pro Shell, and finished it with the industry's smartest design details—watertight zips, articulated sleeves, and seams sonically welded and sealed with gram-shaving micro-tape. The result is the Fission SL, a limited-run storm shelter as warm as a puffy, as waterproof and durable as the best hard shells, and lighter (22 ounces) than anything in its class. It's built for frigid first ascents but will serve you equally well when arctic winds scare everyone else off the lifts. $700; arcteryx.com