When your upcoming alpine adventure requires some serious gram-counting, look no further than the waterproof, breathable Patagonia Ascensionist Jacket for fast and light mountain pursuits. The 3-layer Gore-Tex Active construction ensures lightweight, waterproof, and supremely breathable performance in the unpredictable weather found on high, and also features C-Knit Backer technology to keep you moving quickly in soft comfort. If you work up a sweat, the exposed, watertight two-way underarm vents release excess heat in a pinch with a design that won't ride the hem up when you reach over to unzip them. Your vision won't be hindered by the hood, what, with its helmet-compatible, laminated visor and two-way-adjustable design to provide good visibility in nasty conditions.