Flame™ Ultralight Women's Sleeping Bag

Five VERSIONS for performance in any season

$229.00 – $549.00

What Is This

Sleeping Bag Temperature Ratings Explained

The EN Rating scale is a scientific test to determine the warmth of a sleeping bag. Unisex sleeping bags list the Lower Limit which is the lowest temperature rating that an average male sleeper would be comfortable in. Our women’s sleeping bags list the Comfort Limit, which is the lowest temperature rating at which an average female sleeper should be comfortable. The comfort and lower limit temperature ratings are listed in the features table on the product page.

For example, a unisex sleeping bag that shows a Lower limit of 23ºF means a man should be comfortable down to air temperatures of 23ºF. The same bag will also have a Comfort limit, in the realm of 32°F, so a woman would be comfortable down to an air temperature of 32ºF. Men and women should always sleep in a layer of long underwear and use 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.

Here’s a basic categorization of appropriate use, based on rated temperatures:
Summer:   >+35ºF / +3°C
3-Season:   +10 to +35ºF / -15° to 0°C
Winter:   <10ºF / -15°C

A huge variety of factors can impact sleeping bag warmth - the above temperatures are merely guidelines, not guarantees. It’s important to think of a sleeping bag as one element in a sleep system which also includes an appropriately insulating sleeping pad and a liner. For instance - 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 nights, plus a sleeping mat with an R-Value of 2.5 to 3, and consider a Reactor thermal liner. If you have any questions about which temperature sleeping bag / R-Value sleeping mat you should select, or how to improve your warmth in a sleep system, reach out to us via our contact page any time.


The Flame™ Ultralight Women's Sleeping Bag Series spans everything from an ultralight down-filled liner to a mid-winter fast-and-light sleeping bag. Each model uses premium materials and no-frills design to provide cutting-edge performance for the designed end-use.

The women’s specific fit is narrower at the shoulder and wider at the hip, and features extra down compared to the unisex Spark models.

Is this women's down sleeping bag…?

  • Suitable for cooler temperatures? Yes. You would want the Flame 15°F or possibly the 25°F – either bag will work in late Fall, the 15°F will take you down to early winter temperatures when paired with an adequately insulating sleeping mat.

  • Really suitable as a sleeping bag liner? Yes. You could use the Flame 55°F, or even the Flame 48°F or 35°F to boost the performance of a bag for cold-weather use. Adding one of these to a 20°F / -5°C sleeping bag might make more sense than buying a “0°F / -20°C” sleeping bag for occasional winter use.

  • Able to be zipped to another sleeping bag? No. Even though the 25°F and 15°F have full-length side zippers, they are not designed to be coupled to a sleeping bag with a left zipper.

Read up on the factors which define and affect down quality, and what they mean for you as an end user HERE


Best Use

  • Ultralight Backpacking, Sleeping Bag Liner


  • Sleeping Bag Liner: 55°F (comfort range 55°F to 75°F)
  • Warm Weather: 48°F (comfort range 48° to 68°F)
  • 2 Season: 35°F (comfort range 35°F to 67°F)
  • 2.5 Season: 25°F (comfort range 25°F to 62°F)
  • 3 Season: 15°F (comfort range 15°F to 60°F)

Designed to keep women warm with

  • Down chambers filled using body-mapping to maximize warmth for a woman’s physiology
  • A wider shape between hips and knees to allow you to sleep in a natural position without compressing the down insulation and creating cold spots. 
  • Shorter overall length and narrower girth in shoulders to reduce dead space and increase thermal efficiency


  • ULTRA-DRY Down 850+ Loft 90% Down Cluster Premium Duck Down certified Responsible Down Standard (RDS)
  • 10D shell and 7D liner materials help to achieve the incredible lightweight and compact packed size
  • Includes lightweight Ultra-Sil™ compression bag and storage cell
  • Zipper-length trimmed for gram-saving performance
    • 55°F, 48°F, and 35°F have 1/3-length zippers
    • 25°F and 15°F have full-length side zippers
  • Baffle construction
    • 55°F and 48°F have sewn-through construction.
    • 35°F has baffles in the torso and sewn through in the leg area.
    • 25°F and 15°F are fully baffled.