Kelty Supernova 40

The Kelty Supernova 40 is a duck-down sleeping bag rated to a 4°C limit temperature, weighing 960 g in a semi-rectangular, roomier-than-mummy cut. It has a recycled-fabric lining, opens flat to work as a blanket, and can zip together with another Supernova bag to make a double — useful for couples camping together in mild conditions. Its warmth-to-weight ratio is listed at 4.2, working out to 240 g per degree of rated warmth — a reasonable but not exceptional figure that reflects duck down rather than the higher fill powers used in more compressible, lighter bags. The semi-rectangular shape trades some thermal efficiency for room to move, which matters if you sleep restlessly or want to wear bulkier layers inside. Rated to 4°C, this is a bag for mild three-season nights rather than shoulder-season cold snaps or winter use — pair it with warmer layers or a liner if temperatures might dip further.