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Trek Series

Backpacking sleeping bags don't have to feel like a coffin

$269.00 – $369.00

Size Guide
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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 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 while a woman would be comfortable down to the air temperature of 30ºF, the comfort limit. Men and women should always sleep in a layer of long underwear and use a sleeping mat.

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

There’s a huge variety of factors that can impact sleeping bag warmth, so these ratings are not guarantees. We always recommend choosing a bag that is a few degrees colder than you plan on going out in (choosing a 23ºF bag for 27ºF nights). If you have any questions about which temperature you should select, or how to improve your warmth in a sleep system, reach out to us on our contact page any time.


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The Trek™ Series down sleeping bag collection is a roomy, comfortable and versatile alternative to a conventional mummy sleeping bag. With its tapered rectangular cut, there is plenty of room to move if you happen to be a wriggler. The side and foot box zippers offer excellent ventilation and may be unzipped completely to provide a blanket or quilt style system. The Trek™ bags use 650+ loft RDS certified ULTRADRY Down™, and 2D PermaShell™ outer fabric. A zipper draft tube and clever hood design help to retain warmth. This comfortable, packable and versatile piece of gear would one day recount its tales of wonderful adventuring if it could talk.


Packed Size Comparison

32°F: 5.1 L ≈ A large melon, but not edible
18°F: 6.0 L ≈ A large melon, but not edible
12°F: 7.05 L ≈ Two halves of a rolled yoga mat side by side


32°F: 1 lb 12 oz ≈ Chocolate hazelnut butter in a large jar because why mess with the smaller stuff?
18°F: 2 lbs 2 oz ≈ A quart of cookie dough ice cream
12°F: 2 lbs 6 oz ≈ A quart of cookie dough ice cream


32°F: 2.5 Season - Take this bag out late spring into early fall, no matter where you are.
18°F: 3 Season - Take this bag out in spring, summer and fall, no matter where you are.

12°F: 4 Season - Take this bag out in year round.  Perfect for summer when used as a quilt.


Roomy, lots of room to roll, curl and adjust all night long


  • RDS certified ULTRA-DRY Down 650+ Loft 85% Down Cluster Premium Duck Down
  • Wider in the hips and leg section than a mummy bag for a more comfort-oriented sleep experience
  • Will zip to any Women's Trek™, Latitude™, or Talus™ sleeping bag to form a snug double sleeping bag
  • Full-length YKK® #5 side and foot zip
  • Includes lightweight Ultra-Sil™ compression bag and a combined storage cell/laundry bag