How to Choose Sleeping Bags for Backpacking
Sea to Summit Spark Sp I 40 Down Sleeping Bag
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An ultralight down bag for fast-and-light adventures and mid-summer hut trips, the Sea to Summit Spark Sp 1 down sleeping bag also works well as a liner bag to boost warmth in colder temps.
Shop similar productsKey Details
Fill
850-fill-power goose down
Temperature Rating (F)
40 degrees (F)
- 10-denier shell and 7-denier liner materials help to achieve the incredible lightweight and compact packed size
- Sewn-through baffle construction
- Sewn through vertical baffles on chest optimize position of down to prevent it moving during use
- Half-length zipper with single slider aids access while keeping weight to a minimum
- Updated sizing provides extra room for both shoulders and hips while still maintaining insulation efficiency
- Ethically sourced down; Responsible Down Standard (RDS) Certified
- QuiltLock System compatible; securely connect any Sea to Summit quilt to your sleeping bag to boost your sleep system's performance for colder conditions (quilt not included)
- Includes a Sea to Summit Ultra-Sil Nano compression bag and larger 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 | 40 degrees (F) - ISO |
| Tested Comfort | 48 degrees (F) - ISO |
| Temperature Rating (F) | 40 degrees (F) |
| Temperature Rating (C) | 5 degrees (C) |
| Ultralight | Yes |
| Shell | Nylon |
| Zipper Location | Left |
| Insulation Type | Down |
| Water-Resistant Down | Yes |
| Fill | 850-fill-power goose down |
| Sleeping Capacity | 1-person |
| Lining | Nylon |
| Sleeping Bag Shape | Mummy |
| Stuff Sack Volume | 2.5 liters |
| Gender | Unisex |
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1 year ago
Super light, still strong and solid built!
Super light, strong, soft and just warm enough for Florida; temperature may change quickly in Florida, and still, it only gets pretty cold at the end and beginning of every year; and sometimes our (cold) Winter (60's degrees) is only 2 weeks long! Lemme' tell you, after taking the Spark Sp sleeping bag camping a few times around South Florida, I tell you this sleeping bag is designed for warm weather places; it's very light, almost cloud-soft light; the insulation is extremely thin and very well distributed and I hope such thin insulation lasts, because the softness of the bag has made me sleep in it, even when I was at home (just to test my new camping tent, and this sleeping bag); Jokes aside, I moved furniture around my living room and set up my new camping tent and I slept in it in this sleeping bag for a few days... a couple of weeks, to be more precise; I tested this sleeping bag (using my air conditioner at 69 degrees) to get used to it and because it is 'so' light, it feels flimsy! so far, after about 10 camping weekend trips, it shows no damage at all; I treat my things accordingly, so treating this sleeping bag with a bit of care will make it last for a while; also, I bought the bigger size (this bag is sold in 2 sizes) even though my size is the smaller one, and I did it just in case I need the extra space to help keep something warm, like a pet or an item I must keep close to me (or if I want to wrap myself like a burrito). This bag is awesome!