Outdoors & Fitness · Head-to-head
Feathered Friends Swallow YF 20 vs NEMO Disco 15 Endless Promise
Which should you buy? Our verdict on both, pulled from our full The Best Backpacking Sleeping Bags: 4 Compared (and One to Skip) comparison.
The Swallow YF 20 is the bag to beat on warmth-to-weight and packability, and it is the one serious mile-hikers will not regret. The NEMO Disco 15 is the smarter pick for side sleepers and comfort-first campers willing to carry a bit more.

Feathered Friends Swallow YF 20
Buy itThe warmth-to-weight benchmark: a 20°F rating at a stated 1 lb 13.2 oz average weight.
- 900+ fill-power goose or Muscovy down gives class-leading warmth for the weight
- Pertex YFuse shell, a 20-denier water-resistant Pertex Quantum fabric that Feathered Friends says improves downproofing and water beading
- Lightest bag here at a stated 1 lb 13.2 oz average weight (regular), with a 9 L packed size
- Made in Seattle, USA, of imported materials
- Flagship pricing that is hard to swallow for occasional trips
- A mummy cut, 59 inches at the shoulder, that Feathered Friends places between its narrower Hummingbird and roomier Swift, so side sleepers and larger bodies may feel confined
- Premium down loses loft if it gets soaked and is slow to dry

NEMO Disco 15 Endless Promise
Buy itA spoon-shaped down bag that trades a little weight for the roomiest, most comfortable side-sleeping on trail.
- Classic Spoon shape is cut generously at the elbows and knees for side sleepers
- Thermo Gill vents let you dump heat without unzipping, extending its useful range into warmer nights
- 650 fill-power water-resistant down plus a waterproof-reinforced hood and footbox handle tent condensation well
- Endless Promise design is 100% recyclable at end of life through NEMO
- Heavier than a comparably rated mummy such as the Swallow
- 650 fill power is less compressible than premium 850-plus down
- The 15 in the name is close to its 16°F ISO limit; NEMO states a 27°F ISO comfort rating
Side by side
| Feathered Friends Swallow YF 20 | NEMO Disco 15 Endless Promise | |
|---|---|---|
| Our verdict | Buy | Buy |
| Best for | Weight-counting backpackers and thru-hikers who want the lightest, most compressible real 20-degree bag and will pay for it. | Side sleepers and comfort-first backpackers who value a good night's sleep over shaving every ounce. |
| Price tier | $$$$ · flagship | $$$ · premium |
The bottom line
Our overall pick is the Feathered Friends Swallow YF 20 - The warmth-to-weight benchmark: a 20°F rating at a stated 1 lb 13.2 oz average weight. Choose the NEMO Disco 15 Endless Promise instead if side sleepers and comfort-first backpackers who value a good night's sleep over shaving every ounce.
Want the full picture, including the other options we compared and the popular one we'd skip? Read the complete The Best Backpacking Sleeping Bags: 4 Compared (and One to Skip).