The Cosmic Ultra is the ultimate lightweight mummy. We've taken our top-selling Cosmic bag and added an 800 Fill DriDown version, with all the perks too. The trapezoidal baffle construction is ideal for retaining heat and it's just one of the reasons Cosmic is still our favourite three-season superstar. We also love the natural-fit foot box for happier feet, and a PFC-free water-repellent coating for a healthier environment.