The Spark Ultralight 7 Down Sleeping Bag is a mummy-shaped bag with a no-frill design for efficient insulation and minimal bulk on your lightweight summer adventures. It combines ULTRA-DRY 850+ loft goose down with a soft 10D nylon shell and lining that compresses down small in the included compression sack to take up little room in your pack or bag. It also comes with a storage cell.