Kelty Cosmic Synthetic 40

The Kelty Cosmic Synthetic 40 is the lightest and least warm member of the Cosmic Synthetic line — a synthetic mummy bag with CirroLoft ECO insulation (100% recycled fibers), EN ISO 23537-tested to a 3°C comfort rating. At 1070 g total with just 680 g of fill, it's a summer-into-early-autumn bag for milder nights, where shaving weight matters more than a margin against frost. It shares construction with its pricier siblings: a recycled 20D polyester taffeta shell with DWR treatment, a 50D taffeta liner, a full draft collar, and a draft tube running the full length of the two-way zipper. An adjustable contoured hood, internal pocket, and stuff sack round out the package. Internal length is 198 cm, in a unisex regular fit rated to 183 cm. A warmth-to-weight ratio of 2.8 is on the low side among synthetic bags, confirming this isn't built for cold — but for summer weekend trips and a lighter pack, it makes sense, especially given the recycled materials and lower cost relative to down.