Optimized warmth and minimized pressure points with body mapped insulation Improved shell fabric and lining with PFAS-free water repellent finish Down fill with a PFAS-free water repellent finish throughout the bag provides lofty warmth while synthetic insulation helps alleviate common pressure points in the hips and feet Optimized fit and thermally efficient footbox is patterned to mimic the shape of your foot position while lying on your side Smooth, quick zip with anti-snag locking zipper with no-draft zipper garage, and long, ambidextrous zipper Easily adjust hood without unzipping using low-profile internal cordlock access Seal out drafts by cinching insulated tube along upper hood opening Hang dry or store bags with exterior loops Big Agnes Sidewinder SL 20 Sleeping Bag