Highlights
BEST USE: Backpacking
PERFORMANCE: 3 Season
WEIGHT: 1lb 11.6oz | 782g
COMPRESSED VOLUME: 5.5L
LOWER TEMP RATING: 30°F | -1°C
Product Details
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Testing
Like other quality sleeping bag manufacturers, Sea to Summit tests its sleeping bags for their temperature rating using the ISO 23537 test protocol. This information is presented using the following icon:
The test produces a Lower limit (the temperature a male sleeper should use for orientation) and a Comfort Rating (the temperature a female sleeper should use for orientation). Both are printed inside the sleeping bag and published in the Tech Specs of the sleeping bag webpages.
Sea to Summit Women’s-specific sleeping bags are listed using the Comfort Rating. Unisex bags are listed using the Lower Rating.
What you need to know about the test
A unisex sleeping bag with a Lower limit of 14°F/-10°C should keep a male sleeper comfortable down to 14°F/-10°C provided the sleeper is dressed in heavyweight base layers & insulating cap, and uses a sleeping pad with an appropriate R-Value (for these conditions, at least 4.0)
The same bag will have a Comfort Rating of around 27°F/-3°C, so a woman with the same base layers, cap and sleeping pad would be comfortable down to an air temperature of 27°F/-3°C
These numbers are guidelines, not guarantees. Many factors affect the actual performance. The biggest variable is that the test manikin does not move, where a moving sleeper can draw air into a bag, or compress insulation.
Example
It’s important to think of a sleeping bag, sleeping pad and a liner as a sleep system – combine individual products appropriate for the conditions, and the system will provide the best possible night’s sleep.
If you plan on sleeping in air temperatures of 28°F/-2°C, choose a sleeping bag with a gender-appropriate rating of 23°F/-5°C, add a sleeping pad with an R-Value of 3+, and use a Reactor Liner.
Description
Our most versatile sleeping bag available, in colder temperatures you can cinch down the technical hood, zip up the draft-tube protected zippers and allow the 750+ Ultra-Dry Goose Down to keep you warm. In warmer conditions, the Free-Flow Zip system lets you unzip in different configurations for superior ventilation and even open up flat to turn the Ascent sleeping bag into a quilt on the warmest of nights. All of the above make the Ascent a true three-season backcountry bag, one of very few on the market. Close the snaps at the shoulders, open the footbox zipper and wear the Ascent at camp - hardcore adventures don't have to be hard all the time.
Design Details
Customize your comfort with precision
Unzip, unfold, and effortlessly tweak your airflow and sleeping positions as you adapt to changing temperatures and preferences
Stay in sync with your surroundings
Seamlessly transition from a cocoon of warmth to an open vista of fresh air. Transform your sleeping bag to a quilt, two bags coupled together or back to a standard setup
Move around the campsite with ease
With Free Flow, your sleeping bag becomes your trusted companion as you relax, wander about and bask in the great outdoors. It's more than a sleeping bag—it's an extension of your adventure
Technical Features
750+ Fill Power indicates that one ounce (30g) of down will re-expand to over 750 cubic inches after compression.
The higher the Fill Power, the more the down will insulate for a given weight. This means that less down can be used to achieve the same temperature rating. 750+ goose down represents a good balance between insulation and packability.
Every Sea to Summit down sleeping bag comes with a test report from the International Down and Feather Laboratory IDFL confirming the down loft and quality. All our down is RDS certified responsibly sourced, and hydrophobically treated with a non-PFAS Ultra-Dry Down finish
Our Free Flow triple-zip design ensures your sleeping bag retains maximum warmth and efficiency when needed and multiple ventilation options when it's not. The half-zip on the right side of the bag (left side on women's bags) provides freedom of movement for both arms, additional ventilation and allows the top third of the bag to be folded down as a mini quilt when the mercury climbs higher than expected.
100% of the down used in our sleeping bags and quilts is independently certified to the Responsible Down Standard (RDS). The RDS certifies down against animal welfare requirements and tracks it from the source to the final product. The purchase of RDS certified products demonstrates demand for better animal welfare practices in the down and feather supply chain. Sea to Summit is certified to the RDS. To learn more about RDS visit
Sea to Summit sleeping bag fabrics and insulation are made without PFAS compounds. The non-PFAS DWR finish on the shell helps prevent the insulation from becoming damp if the bag comes into contact with mositure, such as tent wall condensation.
Ultra-Dry Down is a non-PFAS hydrophobic treatment that absorbs less moisture and dries more quickly. It does not affect the 'breathability' or the lifespan of the down and lasts through at least 20 washings. The down used in our sleeping bags is responsibly sourced.
Sea to Summit Dry Bags, Stuff Sacks and Compression Bags use a non-PFAS Durable Water Repellent finish to help shed water. Big River bags use a non-PFAS PU coating.
Tech specs
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Best UseBackpacking
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Comes With40D recycled, bluesign APPROVED nylon compression bag
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InsulationRDS certified, 750+ non-PFAS Ultra-Dry Down
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ShapeRelaxed mummy
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Zip OptionsFree-Flow zipper system
-1°C Regular | -1°C Long | -9°C Regular | -9°C Long |
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Excellent insulation and warmth
Frequently Asked questions
Is the Ascent suitable for colder weather?
Yes - the -9°C/15°F version has high-lofting down, a technical hood and draft tubes that make it great for extended three-season use.
Is the Ascent comfortable in warmer weather?
Yes! The Free-Flow zippers can be opened sequentially for ventilation or to open the bag completely flat as a quilt.
Can the Ascent be zipped to another sleeping bag?
Yes - the Unisex Ascent can be coupled with a Women's Ascent, or zipped together with most STS Women's sleeping bags
Shipping & Returns
Free express delivery in Australia for orders over $99.99*.
For all other orders under $99.99, we charge a flat fee of $10.00 for delivery in Australia.
For more details, check out our Shipping Policy.
We do not ship to an address outside of Australia.
If you are not entirely satisfied with your order, you may be entitled to a refund of the purchase price of the Product. For more details, please check out our Refund Policy.