The Swift UL 20 is Feathered Friends' roomiest mummy bag, built with the same wide cut as the rest of the Swift line but pushed to a -7°C limit rating. It carries 529 g of 950 fill-power RDS-certified goose down for a total of 823 g — more fill and more weight than the Swallow bags, in exchange for both extra warmth margin and extra shoulder room.
The shell is the 7D/30D Pertex Quantum Pro used across Feathered Friends' UL models, backed by a Flyte 10D recycled nylon liner, with continuous baffles, a full-length two-way zipper, draft collar and draft tube, and a fitted, contoured hood sized for a 183 cm user. A trapezoidal foot box adds volume without extra fabric weight. Both stuff sack and storage sack are included, and the shell is PFC-free.
At 823 g for a -7°C rating, this is a three-season bag for restless sleepers who want the wider cut, not a race-weight ultralight. Made in the USA from recycled and RDS-certified materials, it targets thru-hikers prioritizing comfort as much as pack weight.