BEST USE: Backpacking
PERFORMANCE: 2.5 Season
WEIGHT: 2lbs 6.1oz | 1080g
COMPRESSED VOLUME: 6.5 liters
Shipping & Returns
Free express delivery in Australia for orders over $49.99*.
For all other orders under $49.99, we charge a flat fee of $10.00 for delivery in Australia. We do not ship to an address outside of Australia.
For more details, check out our Shipping Policy.
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.
The EN Rating scale is a scientific test to determine the warmth of a sleeping bag. The test produces a Lower rating (for male sleepers) and a Comfort rating (for female sleepers). Both are listed in the features table on the product page.
A unisex sleeping bag with a Lower limit of 14ºF means a man should be comfortable down to air temperatures of 14ºF. The same bag will also have a Comfort limit, in the realm of 27°F, so a woman would be comfortable down to an air temperature of 27ºF. These ratings require a sleeping mat with an R-Value appropriate for expected ground temperatures – without this, the sleeping bag itself is unlikely to keep the sleeper warm enough.
A variety of factors impact sleeping bag warmth - the above temperatures are merely guidelines, not guarantees. It’s important to think of a sleeping bag, an appropriately insulating sleeping pad and a liner as a sleep system. For example - if you plan on sleeping in nighttime air temperatures of 27ºF / -3°C, choose a bag with a gender-appropriate rating of 23°F / -5°C, plus a sleeping mat with an R-Value of 2.5 to 3, and consider a Reactor thermal liner.
Incredibly versatile, the Altitude women's down sleeping bag is snug and cozy when it's cold, and cool and ventilated when the weather warms. Shaped to match your natural sleeping position the Altitude is both comfortable and light enough to carry anywhere.
DESIGNED FOR WOMEN
Shaped for comfort
Narrower at the shoulders, wider between the hips and knees. Regardless of the position you sleep in (figure-four, on your side or on your stomach), this shape provides a significantly higher level of comfort by giving you the room to move without compressing the insulation.
Warmth from additional insulation
Additional insulation compared to unisex bags, positioned using different body mapping for thermal performance exactly where it is needed. The comfort and versatility-oriented Journey and Altitude sleeping bags have an additional Thermolite layer in the footbox to warm your feet fast. Temperatures for Women’s sleeping bags are shown using the gender appropriate Comfort rating.
Maximum comfort for a good night's rest
Construction details like snug-fitting hoods and oversized draft tubes keep you warm in cooler weather. As temperatures rise, the Free-Flow zipper system of the Journey, Venture and Altitude allow you to increase ventilation up to the point where the bag opens completely flat as a quilt. Super-soft fabrics are comfortable in any season.
You don’t have to narrow your options with a constrictive mummy bag – expand your horizons with a sleeping bag which fits the way you sleep.
Comes WithUltra-Sil compression bag and storage cell
InsulationUltra-Dry Down 750+ Loft
Shell FabricLightweight 20D Nylon Shell
Zip OptionsFree-Flow zipper system
|Altitude I (-4°C) Regular||Altitude I (-4°C) Long||Altitude II (-10°C) Regular||Altitude II (-10°C) Long|
The second highest-lofting down used in any of Sea to Summit’s sleeping bags or quilts. 750+ Fill Power indicates that one ounce (30g) of down will re-expand to over 750 cubic inches after compression. Higher loft means that less down can be used to achieve the same temperature rating – important for performance sleeping bags. The loft and down quality/composition are independently tested by the International Down and Feather Laboratory (IDFL) – a copy of the certification is supplied with every Sea to Summit sleeping bag. The down is responsibly sourced and RDS certified and treated with our non-PFC Ultra-Dry Down™ treatment.
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
Thermolite® HL-1 is part of the family of Thermolite® materials used in Sea to Summit sleeping bags, sleeping bag liners and sleeping mats. HL-1 high loft insulation is a fiberfill constructed with a unique 3D crimp of hollow-core and solid fibers, which provides excellent lightweight warmth with superior durability. The Thermolite insulation lofts up inside the Air Sprung Cells™ of our sleeping mats to prevent convective heat loss from your warm body to the cold ground.
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.
Sea to Summit hydrophobic down and DWR finishes are Non-PFC.
The down is RDS-certified responsibly sourced. The non-PFC Ultra-Dry Down™ hydrophobic treatment means it absorbs less water than untreated down and dries much more quickly. Ultra-Dry Down does not affect the loft or lifespan of the down, or its breathability. The treatment will last through at least 20 washings
Non-PFC DWR Shell fabric:
Despite being incredibly lightweight, the 10 Denier UL Nylon is down-proof and surprisingly durable. A non-PFC DWR finish helps the shell to shed external moisture. This fabric is part of the secret to making the Spark and Flame Down Sleeping Bags and the Ember Quilt Series some of the lightest, most packable sleep system products available today.
Frequently Asked questions
Warm enough for shoulder seasons?
Yes. The high-lofting down, cozy hood and draft collar, and extra Thermolite® insulation in the foot box provide the warmth you need for cold weather. For cold weather, we recommend the Altitude -10°C paired with a greater than 3.5 R-Value sleeping mat like the Women's Comfort Light Insulated.
Really cool in summer temperatures?
Yes. The Free-flow zipper system means separate zippers on your left and right side and in the foot box. Open them for ventilation or turn the Altitude into a comforter.
Able to be zip together with another sleeping bag?
The main side zipper can be zipped to Sea to Summit Ascent, Trek or Traverse sleeping bags. The Altitude Regular and Long bags have the same side zipper length.