The (Backpacking) Intersection of Light Weight and Warmth Let’s face it- when is backpacking ever actually easy? While we can’t take the pain out of your elevation gain, we CAN put you on the trail with the new Cosmic Synthetic 40 Sleeping Bag. It’s a fully equipped mummy bag that’s light on weight and your wallet. The Cosmic synthetic is a three-season superstar built with our new CirroLoft synthetic insulation for lightweight, compressible warmth. Soft-as-silk nylon taffeta fabric means you’ll be thinking less about weary hiker feet and daydreaming about more QT in the outdoors.