The same versatility you love with even more down loft to keep the colder backcountry conditions at bay. Its perfect balance of functionality and warmth make it ideal for three-season backcountry adventures or for layering in colder conditions. Made with high loft, packable Nikwax Hydrophobic Down and Box Baffled construction for retaining heat and excellent temperature regulation, the Corus offers a surprisingly liberating feeling of unrestricted movement throughout the night. The footbox can slip over your pad to eliminate drafts or over your feet for extra warmth. 650 Fill Nikwax Hydrophobic Down: Absorbs 90% less water and dries 3 times faster without using dangerous PFCs. Compact: Designed to easily fit into your pack. Box Baffled Construction: Uses mesh walls to maximize down loft and minimize cold spots. SynergyLink Connectors: Removeable ultralight straps create a secure bag-to-sleeping pad connection that optimizes the comfort and thermal efficiency of your entire sleep system