A very light down mummy bag that packs small for its warmth. People pick it for shoulder-season backpacking when weight and pack space matter most.
Specs
- Weight: 730 g / 25.7 oz (15°F Regular)
- Fill: 480 g of 850+ fill-power RDS-certified goose down, Ultra-Dry treated
- ISO comfort: 28°F; ISO limit: 16°F
- Shell: 10D nylon, non-PFAS DWR
- Compressed volume: 6.8 L
- Sizes: Regular, Long, Double; also 45°F, 30°F and 0°F versions
- Price: $349 (maker, Oct 2026)
What reviewers say
CleverHiker's 2026 guide names the Spark 15 its best ultralight sleeping bag. Testers praise the low weight, tiny packed size and strong warmth for the weight, and like the included compression sack. They warn the thin shell needs care, the zipper can snag, and the price is high.
Good
- Very light and packable
- Warm for its weight
- Responsibly sourced down
Not so good
- Thin, delicate shell
- Zipper can snag
- Costly
Who it's for
Backpackers who want to cut weight for spring and fall trips. Restless sleepers or car campers will be more comfortable in a roomier bag.
Sources
Last checked 2026-10-19. Specs from the maker; review notes summarized in our own words.