Designed for late spring to early fall use, the Sea to Summit Spark Ultralight 18F sleeping bag is a lightweight pick for ounce-counting backpackers. It serves up easy ventilation and cozy comfort.
Fill
Ultra-dry down
Temperature Rating (F)
18 degrees (F)
- 850-fill-power down provides cozy warmth
- Baffles in the torso area keep insulation in place; sewn-through construction in the leg area helps keep this bag lightweight
- 10-denier shell and 7-denier liner materials deliver an impressively light weight and compact packed size
- Full-length side zipper with 2 sliders offers easy ventilation options
- Includes lightweight Ultra-Sil™ compression bag and storage cell
Imported.
Temperature ratings are intended as a guideline to help you compare products, rather than a guarantee of warmth, since many different factors contribute to your comfort while you sleep. Backpacking bags are typically rated for temperature according to an independent testing protocol—currently International Organization for Standardization (ISO) 23537, though some older items followed European Norm (EN) 13537. Testing is based on a person wearing one base layer and a pair of socks, sleeping on an insulated surface with a minimum R-value of 5.38.
Each bag then gets 2 ratings: the Comfort rating is the lowest temperature at which the bag will keep the average "cold sleeper" comfortable, and the Lower Limit rating is the lowest temperature at which the bag will keep the average "warm sleeper" comfortable. Some brands determine their own temperature rating by aligning to the Comfort rating for women’s bags, to the Lower Limit rating for men’s bags, or somewhere in the middle for nongendered bags.
View all Sea to Summit Backpacking Sleeping BagsEach bag then gets 2 ratings: the Comfort rating is the lowest temperature at which the bag will keep the average "cold sleeper" comfortable, and the Lower Limit rating is the lowest temperature at which the bag will keep the average "warm sleeper" comfortable. Some brands determine their own temperature rating by aligning to the Comfort rating for women’s bags, to the Lower Limit rating for men’s bags, or somewhere in the middle for nongendered bags.
| Best Use | Backpacking |
|---|---|
| Tested Lower Limit | 18 degrees (F) - EN |
| Tested Comfort | 29 degrees (F) - EN |
| Temperature Rating (F) | 18 degrees (F) |
| Temperature Rating (C) | -8 degrees (C) |
| Ultralight | Yes |
| Shell | 10-denier nylon |
| Zipper Location | Left |
| Insulation Type | Down |
| Water-Resistant Down | Yes |
| Fill | Ultra-dry down |
| Lining | 7-denier nylon |
| Sleeping Bag Shape | Mummy |
| Stuff Sack Size | 6 x 14 inches |
| Stuff Sack Volume | 6 liters |
| Gender | Unisex |