Designed with thru-hikers, bike packers, and weight-conscious adventurers in mind, the Firefly is incredibly effective for its size. Its Pertex Quantum outer is made using their Y Fuse technology to increase durability, and a DWR finish encourages water to bead and roll off its surface. The lining is bluesign certified.220g of 800 loft HyperDRY RDS goose down provides high-quality warmth that packs incredibly well, and its wide adjustable opening eliminates the need for zips (that inevitably increase weight). Packed dimensions and weights are based on when sleeping bags are purchased, they can be further compressed. This sleeping bag comes with a compression-style stuff sack and a mesh storage bag. Its temperature ratings have been tested to the international ISO 23537-1 standard. It's also made in a standard size. Check the size guide for a full breakdown of measurements. bluesign certification means this fabric has been manufactured with the responsible use of resources. A zipperless down sleeping bag, highly compressible for lightweight adventures.