When it comes to trapping heat with minimum weight, goose down has precious little competition. It’s nature’s best insulator and it has only one flaw – when it gets wet, its warming power gets hampered something fierce. We fixed it with the Aniak. The 650-fill-power down inside this vest is treated with a durable water repellent, so it stays lofty and toasty even in freezing wet conditions. Defended by a Pertex shell that’s soft yet seriously rugged, sheds water and blocks gusts. It makes for a vest that sheds the weight without sacrificing warmth, and packs down tight when you need to squeeze into a prop plane for your next adventure. And when you’re dealing with whiteout conditions? It snaps inside the Williwaw Stretch Shell for complete protection from the worst winter has to offer.