Trapezoidal baffle construction provides enhanced thermal efficiency Lofty, lightweight and warm 550 Fill Down Buttery-soft and durable, fully-recycled shell and liner fabrics with PFAS-free DWR Zippered internal stash pocket keeps your favorite devices close at hand 0° full draft collar and 20° upper draft collar work to retain heat 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, fully recycled fabrics, and PFAS-free DWR treatment. The Cosmic Down is the total package.