Based in Seattle, Feathered Friends knows a thing or two about staying warm and dry. The Filson x Feathered Friends Sleeping Bag draws on this experience to create a capable outdoor collab. Filson's 6 oz. dry finish cover cloth is used for the gray outer shell, while the snap-in inner liner is made from 8-oz. Alaskan Guide cotton flannel. In between is a layer of nylon taffeta, and for added protection in the harshest weather, there's a zipper-attached condor hood.