OUR CLASSIC BEST-SELLER - THE PERFECT BALANCE OF LIGHTWEIGHT WARMTH Remember the trapezoid from high school geometry? Turns out, this funky ol' shape is ideal for helping sleeping bags retain heat. Our trapezoidal baffle construction is just one of the reasons the Cosmic Down is still our favorite three-season superstar. We also love the expanded natural-fit footbox for happier feet, zippered stash pocket and fully recycled fabrics and PFAS-free DWR treatment. The Cosmic Down is the total package.