Belay duty's never exactly fun, and it's even less exciting when you're sitting there in a blizzard for three hours while your partner searches his way up the first pitch of a rime coated cliff. Luckily, the Rab Infinity Endurance Women's Down Jacket will protect you from the cold and snow, even during the most unpleasant belays you've ever experienced. Decked out with super light and water resistant Pertex Quantum GL and Pertex Endurance fabrics, the Infinity will resist moisture, but it's also been absolutely loaded up with 850 fill hydrophobic down, so you'll stay warm even if your jacket does get a little big soggy. Since the down's so lofty and the fabric's so light, the Infinity weighs just over one pound, so you'll hardly notice it's there when you're wearing it, let alone when you've packed it into its stuff sack and hidden it away in your pack. Lightness doesn't mean the Infinity is bare bones, though. It has all the technical features you'd expect in a big time alpine expedition jacket, like an adjustable and helmet compatible hood with a wire brim, an miniature baffle behind the front zipper, and elasticated cuffs and a hem drawcord to keep snow and drafts from sneaking into your downy comfort zone. Four zippered pockets give you enough room to store essentials like snacks, lip balm, and gloves, and the regular fit's roomy enough to allow for layers without drowning you in extra fabric. When you need seriously light warmth in rugged alpine conditions, the Infinity's a tough jacket to beat.