The Tanager 20 CFL strips a sleeping bag down to its essentials: no hood, no zipper, just a tapered quilt-style shell holding 359 g of 950 fill-power RDS-certified goose down for a -7°C limit rating at only 537 g total. Removing the zipper and hood cuts both weight and the cold spots those features can create, which is why the warmth-to-weight figures here are well ahead of Feathered Friends' zippered mummy bags.
The 7D Pertex Quantum ripstop shell and 15D Flite ripstop liner keep fabric weight minimal, with a draft collar sealing the open top but no draft tube, since there's no zipper to guard. Sized for users up to 172 cm, it packs down with the included stuff sack and comes with a storage sack for long-term care. Made in the USA.
This is a purpose-built ultralight quilt for thru-hikers and alpine climbers counting every gram, best paired with a sleeping pad and some technique for managing drafts at the open sides — not for hikers who want the enclosed security of a full mummy zip.