The verdict
The Spark 0 is the best-overall pick — Sea to Summit's lightweight zero-degree bag with 850 fill.
Strengths
- +Exceptional warmth-to-weight ratio
- +850 fill power down
- +10d nylon shell — lightest in lineup
- +Compact packed size
Watch-outs
- −Premium pricing
- −10d shell less durable than thicker fabrics
- −Hand-wash recommended
How it compares
Best warmth-to-weight. Lightest shell. Premium.
Who this is for
At a glance: ultralight backpackers prioritizing pack weight.
Why you’d buy the Sea to Summit Spark 0
- Exceptional warmth-to-weight ratio.
- 850 fill power down.
- 10d nylon shell — lightest in lineup.
Why you’d skip it
- Premium pricing.
- 10d shell less durable than thicker fabrics.
- Hand-wash recommended.
Rating sources
Our 4.7 score is the average of these published ratings. More about methodology.
