Sea to Summit Spark 0-Degree Down Sleeping Bag, Regular: Weight, Price and Alternatives
The Sea to Summit Spark 0-Degree Down Sleeping Bag, Regular has a published weight of 2 lb 1 oz and a listed price of $649.00, which is about 21 percent of a 10 lb ultralight base weight.
The Sea to Summit Spark 0-Degree Down Sleeping Bag, Regular is one of the verified picks in cold weather sleeping bags, with a published weight of 2 lb 1 oz and a listed price of $649.00. A 0 degree rating at roughly two pounds, which is what down at very high fill power buys you. Temperature ratings assume a warm pad under you, so pair it with an R value of 5 or better or the rating means nothing.
What is the Sea to Summit Spark 0-Degree Down Sleeping Bag, Regular actually good at?
A 0 degree rating at roughly two pounds, which is what down at very high fill power buys you. Temperature ratings assume a warm pad under you, so pair it with an R value of 5 or better or the rating means nothing.
A cold weather bag only performs to its rating over a pad that matches it. Below freezing that means an R value of 5 or better, which in practice means two pads, because the ground pulls heat out faster than the air ever will.
What does it do to your base weight?
At 2 lb 1 oz this item accounts for roughly 21 percent of a 10 lb ultralight base weight and about 10 percent of a 20 lb traditional one. That framing matters more than the raw number: an ounce saved on a headlamp is noise, and a pound saved on a shelter is a category of its own. Put your real figures into the gear list builder and the same item will show you what it costs against your list rather than against an average one.
Published weights are taken in the manufacturer's favour: usually the smallest size, usually without the stuff sack, stakes or guylines that come in the box. Expect a real-world figure an ounce or two heavier and weigh it once when it arrives. A $9 kitchen scale is the cheapest useful upgrade to any gear list, because it stops the spreadsheet lying to you.
What does the temperature rating actually mean?
Cold weather ratings published to EN 13537 or ISO 23537 are survival ratings, not comfort ratings, and the gap matters more the colder it gets. The published limit is roughly where an average sleeper survives the night curled up, the comfort figure usually sits 10 to 15 degrees Fahrenheit warmer, and the extreme rating is a survival-with-injury number that has no place in trip planning. Below freezing the pad decides whether the bag performs at all: pair a cold weather bag with an R value of 5 or better, which in practice means stacking an inflatable on closed cell foam, because R values add.
Which complete kits use it?
This item appears in one of the complete gear lists on this site, which is the most useful context a single product page can give you: not what it weighs in isolation, but what share of a finished kit it accounts for and what the rest of that kit looks like around it.
| Complete kit | Season | Kit base weight | This item | Share of base | Kit cost |
|---|---|---|---|---|---|
| Winter | Winter and cold shoulder season | 17 lb 2.9 oz | 33.0 oz | 12% | $4501.70 |
Every one of those kits lists every item you need to actually go, with a per item weight and price, a running total down both columns, a section on what you can skip, and an upgrade ladder priced in grams saved per dollar. Each also loads straight into the gear list builder so you can swap this item for something you already own and watch the total move. That is usually a faster way to decide whether a purchase is worth it than reading another review of it.
Who should skip it?
Anyone whose conditions sit well outside what this item is built for. Nothing here is a universal answer, and the honest failure mode of a gear list is not weight, it is a piece of kit that was chosen for a different trip than the one you are taking.
Going lighter must not mean going unprepared. Shelter adequate to the actual conditions, insulation, rain protection, water treatment and a way to call for help are fixed costs on any list. If a lighter version of this item means cutting into one of those, it is the wrong purchase however good the spec sheet looks. You are responsible for what you walk into, and the forecast is not the conditions.
Related reading
- Our full cold weather sleeping bags roundup, split into beginner, intermediate and expert tiers
- Temperature rating chart
- Cold weather ultralight guide
- Gear list builder: see what this item does to your own base weight
- Base weight calculator
- Six complete example gear lists, every item priced and linked
- All verified gear specs, A to Z
Frequently asked questions
How much does the Sea to Summit Spark 0-Degree Down Sleeping Bag, Regular weigh?
The published weight is 2 lb 1 oz, which is 33.0 ounces or about 936 grams. That is roughly 21 percent of a 10 lb ultralight base weight on its own. This figure is the manufacturer's for the size and configuration named, not a weight we measured, and published figures run light often enough that it is worth putting your own scale under it.
Is the Sea to Summit Spark 0-Degree Down Sleeping Bag, Regular worth the money?
A 0 degree rating at roughly two pounds, which is what down at very high fill power buys you. Temperature ratings assume a warm pad under you, so pair it with an R value of 5 or better or the rating means nothing. At the listed $649.00 it sits at the expensive end of its category, and prices move constantly, so confirm before you buy.
Where can you buy the Sea to Summit Spark 0-Degree Down Sleeping Bag, Regular?
Backcountry carries this category and is the first link on this page, because it is where this audience shops and it pays us a higher commission than Amazon does. Amazon is the second button. Stock and pricing differ between the two often enough that checking both is worth the extra thirty seconds.
What does the Sea to Summit Spark 0-Degree Down Sleeping Bag, Regular compete against?
This item does not have a direct equivalent in our verified set, which usually means it is a category of one rather than a best-in-class pick. The roundup linked below covers the wider category and where this sits inside it.
Are the weights on this page measured or published?
Published. We compare manufacturer specifications and verified owner reviews, and we do not test gear in person or run a gear lab. Manufacturer weights are usually taken from the lightest size, without stuff sacks, stakes or guylines, so a real-world figure is often an ounce or two heavier. Weigh your own kit and put the real numbers into the gear list builder.
How we choose: we compare published manufacturer specifications, listed weights, and verified owner reviews across retailers. We do not test gear in person, and every weight quoted here is the manufacturer's figure unless we say otherwise, so weigh your own kit before you trust a total. Going lighter also means carrying less margin, so treat insulation, navigation, water treatment and an emergency plan as fixed costs rather than places to save grams.