When you're moving fast and light in the mountains the Patagonia Ascensionist GTX Jacket keeps you mobile and protected from the elements. It is constructed with a Gore-Tex Active membrane to shed grams while still providing waterproof protection in rain showers. This membrane is enhanced with a Gore-Tex C-Knit backer to keep the jacket soft and supple for extra comfort as you climb hike or scramble your way to the summit. When you're harnessed in for a climb the external pockets are comfortably accessible for easy access to your snacks phone or other small essentials. And when the ascent gets strenuous underarm ventilation zippers allow you to quickly and easily dump excess heat so you can push on to the summit more comfortably.