Mammut Relax Fiber Bag -2C review: a comfortable and versatile sleeping bag for casual camping

A fairly technical but whimsical sleeping bag, the Mammut Relax Fiber Bag -2C performs well in a range of situations

Mammut Relax Fiber Bag -2C
(Image: © Mammut)

Advnture Verdict

Supremely comfortable and very versatile, the laid-back Relax sleeping bag makes bedtime a pleasure during casual camping forays and road trips.


  • +

    Very user friendly

  • +

    Women’s specific version available

  • +

    Ajungilak fiber filling impervious to moisture


  • -

    Not as well suited for big backcountry adventures as some other bags

You can trust Advnture Our expert reviewers spend days testing and comparing gear so you know how it will perform out in the real world. Find out more about how we test and compare products.

Mammut Relax Fiber Bag -2C: first impressions

Essentially a fair-weather sleeping bag, the fun and funky Mammut Relax Fiber Bag -2C is made for warm summer nights boondocking in a camper van and chilling by the campfire.

The fit of this bag is comfort-focused. A central zipper makes it easy to get in and out of and allows for on-the-fly temperature regulation (see: Sleeping bag temperature ranges explained). The synthetic hydrophobic lining and filling won’t absorb moisture, and the iridescent outer fabric and T-shirt soft shoulder and neck lining aren’t crinkly and loud (thankfully).

Mammut have designed a new anatomical footbox for this bag, to give sleepers more space without adding extra weight (see: Types of sleeping bag). They also added a modest draft tube to keep the cold out. The 100% polyester bag is bluesign approved, with a PVC-free durable water repellent. It’s Fair Wear certified and as a brand Mammut strives to ensure fair and safe working conditions in all factories making its products.


RRP: $200 (US) / £170 (UK)
Weight: 720g / 1lb 9oz
Length: 205cm / 80.7in
Max user height: 172cm / 68in
Packsize: 27 x 22.5cm / 10.6 x 8.86in
Fill: Mammut’s synthetic Ajungilak 100% Polyester insulation
Comfort: 3°C / 37°F
Limit: -2°C  / 28°F
Compatibility: 2 to 3-season

In the field

The anarchic purple and pink design of this bag (I tested the women’s version – see: Best women’s sleeping bags) is not just eye-catching, I also found it to be spacious and comfortable, and it quickly became my go-to user-friendly bag for use camping at my favorite surf break, and couch surfing on a cross-country road trips.

The recycled-content synthetic fill bag has a full-length zipper. As a result I could unzip from the bottom when I wanted to wander but didn’t want to get out of my bag, which was at home around the campfire as well as in the tent.

Where a lot of bags seem too technical for impromptu summer outings, this one always fits right in. The T-shirt-soft material around the neck was cozy, not crinkly. A snap at the top of the zipper didn’t get caught in my hair as Velcro tabs on most bags do. And the stash pocket not only held my headlamp, but a paperback, my wallet, and my phone too.

This might not be the bag for scaling Everest, but it is the bag to keep in the back of the car for anytime adventures.

Berne Broudy

Vermont-based writer, photographer and adventurer, Berne reports on hiking, biking, skiing, overlanding, travel, climbing and kayaking for category-leading publications in the U.S., Europe and beyond. In the field, she’s been asked to deliver a herd of llamas to a Bolivian mountaintop corral, had first fat-biking descents in Alaska, helped establish East Greenland’s first sport climbing and biked the length of Jordan. She’s worked to help brands clean up their materials and manufacturing, and has had guns pulled on her in at least three continents.