When it comes to serious expedition backpack hunts, there's no skimping on your sleeping bag, so we build to surpass the requirements. The Super Down Altai Sleeping Bag is made from the highest-quality materials, combined with superior design elements, all while maintaining a packable size and ultralight weight. It starts with our legendary Quixdown® insulation made from premium Eastern-European goose down that's sourced from regions where geese grow the largest and warmest plumes in the world. The down is cleaned, perfected, and treated with the industry's best-performing DWR so it won't wet out, even in the IDFL's seemingly unpassable water-shake test. Leveraging your own body heat, the all-new interior is made from a revolutionary aluminized fabric for ultimate heat reflection and retention. The outer shell is spec'd with an ultralight, strong, and 100% windproof fabric, that won't let moisture in thanks to its top-performing K-DWR® water-resistant finish. The bag is designed with a combination of chevron shaped horizontal and vertically oriented box-baffles that keep the down from migrating or shifting, effectively eliminating cold spots. For increased heat retention and comfor