Sea to Summit Spark Ultralight Down Sleeping Bag
- 13.6 oz bag weight
- 850+ fill power down, RDS certified, Ultra-Dry treated
- Mummy shape, 77.2 x 30.5 inches
- Sleepers up to 6 feet
- Summer season bag, temperature rating not listed
- Lifetime warranty against defects in materials or workmanship
Last refreshed Sep 28, 2026 · Based on the Amazon listing and published specifications, not hands-on testing.
A very light summer down bag for backpackers counting every ounce, with Ultra-Dry treated down. It is a warm weather bag only, and the listing gives no temperature rating to plan around.
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ASIN: B0CTD455LJCategory: Sleeping Bags
Sizes Available
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Overview
Packing light for summer backpacking trips is what the Spark is built for: a contoured mummy bag filled with high-loft down and closed with a zipper. The nylon shell wraps a single sleeper, and the Ultra-Dry treatment is applied to the down itself.
Weight is the reason to carry it, since high-loft down gives warmth at a very low pack weight. The limits are the summer season rating, the snug mummy cut and the missing temperature figure, so cold nights or roomy sleepers call for a different bag.
Who it's for
Lightweight hikers on warm weather trips get down warmth in a bag that adds little to the pack. Taller sleepers, restless sleepers who sprawl, and anyone camping in cold conditions should choose otherwise.
Pros and cons
- Very low carry weight
- High fill power RDS certified down
- Ultra-Dry treated down
- Contoured mummy cut reduces dead air
- Temperature rating not listed
- Summer season only
- Mummy cut restricts movement
- Too short for taller sleepers
Performance notes
Warmth comes from loft: high fill power down traps more air per ounce, and the contoured mummy shape trims the space the body has to heat. Down loses loft when wet, which the Ultra-Dry treatment is meant to slow. An insulated pad matters too, since compressed down under the body adds little warmth.
Where it stands among sleeping bags
- #2 most-searched brand and model of the 30 sleeping bags lines we track (by search demand, not sales).
From the specs of the 83 sleeping bags we list; not a test result.
Specifications
| Brand | Sea to Summit |
|---|---|
| Dimensions & fit | |
| Maximum Height Recommendation | 72 incheslower than 53% of 33 sleeping bags |
| Size | Standard |
| Item weight | 0.85 poundslower than 100% of 33 sleeping bags |
| Item Dimensions L x W | 77.2 × 30.5 inches |
| Construction & materials | |
| ShellMaterial | Nylon |
| Color | Grey |
| Warranty & support | |
| Warranty Description | Lifetime |
| Other details | |
| Occupancy | 1 Person |
| Shape | Mummy, Contoured |
| Closure Type | Zipper |
| Sport Type | Backpacking |
| Seasons | Summer |
Closest rivals on specs
Western Mountaineering MegaLite 30F Down Sleeping Bag- Item weight 0.85 vs 1 pounds (-15%)
Western Mountaineering TerraLite 25 Degree Sleeping Bag- Item weight 0.85 vs 1 pounds (-15%)
Western Mountaineering EverLite Down Sleeping Bag 45F- Item weight 0.85 vs 1.1 pounds (-23%)
Frequently asked questions
Can the Sea to Summit Spark be used outside summer?
The specs rate it for summer only and list no temperature rating, so plan on warm nights or carry extra layers for cooler ones.
Does the Sea to Summit Spark fit two people?
No. Occupancy is listed as one person.
What is the Spark sleeping bag shell made of?
Nylon, per the specs, with a zipper closure.
Does the Spark come with a stuff sack?
The listing does not name any included stuff sack or storage sack.