REI Co-op Magma 15 Review

Our REI Magma 15 Experience

We spent several nights sleeping in the REI Magma 15 during a spring trip to Chulilla, Spain, and while climbing a big wall in Yosemite Valley. During cold nights throughout spring, it kept us cozy and warm inside this down sleeping bag. The water-resistant finish was especially appreciated in open bivouacs, effectively protecting the down inside the bag and keeping us warm.

While it's not the lightest sleeping bag that we tested, it was light enough for our four-week backpacking trip in Spain. The lofty down was easy to compress into a stuff sack inside our backpack.

After several days of pushing our mental and physical limits while climbing on a big wall, we appreciated the supple and cozy interior of the Magma 15, making it easier to rest and recover after big days.

Analysis and Test Results

Warmth

Having the right fit significantly impacts the warmth of a bag, and the Magma 15 is the most customizable bag we've tested, as it comes in nine different sizes—so you're all but guaranteed to find the right fit. This bag is perfectly contoured to our body, and leaves little to no room for cold air, making for a cozy, draft-free night's sleep. It has 850 down goose fill power, meaning it has top-tier insulating properties without adding much weight. This design, combined with a large contoured hood, extra insulation within the toebox, and an insulated collar, all contribute to a warm night's sleep, even in colder temps. The Durable Water Repellant finish protects the down feathers and keeps us warm even when dew and frost accumulate through the night.

We agree with the 28°F comfort rating of Magma 15 that's best-suited to optimize warmth when temperatures hover around freezing, making it a great bag for three season use. And if you're using it in warmer temperatures, it features a dual, two-way, full-length zipper so you can open up the bottom of the bag for better air circulation.

We have a few small complaints about this design, namely that the insulated neck baffle sometimes blocked our face throughout the night. The baffle along the main zipper also has a tendency to let in a slight draft when we fully stretch out inside the bag. And finally, the large hood has to be tightened more than we'd like in order to trap body heat during the coldest nights of testing. Overall, we think this is a great three season down-filled construction for those seeking custom warmth and thermal efficiency when the temperatures are right around 32°F.

The lofty 850 FP goose down design along with customizable sizing kept our testers warm and toasty.   Credit: Trish Matheny

The customizable sizing and baffles along the hood and zipper trapped body heat.   Credit: Trish Matheny

The neck baffle design is great when you get it in the right spot.   Credit: Trish Matheny

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Weight

The Magma 15 weighs in at 2.36 pounds in the Medium Narrow, which isn't the lightest down construction, but it remains competitive with premium bags and is packable enough that we wouldn't mind carrying it on longer trips into the backcountry.

It's clear that a ton of thought went into managing the weight and size of the Magma 15 to enhance warmth and comfort without sacrificing its versatility. The custom sizing allows you to select the best dimensions for your body, so as to maximize thermal efficiency without carrying any extra weight into the mountains.

Comfort

The Magma 15 is the perfect down sleeping bag for those seeking abundant comfort through its highly customizable design. With up to nine sizing options within one design, you can select the most comfortable option for your body type. The soft, supple, and cozy interior combines with a high loft that makes us feel like we're inside a cocoon, even in uncomfortable temperatures. The trapezoidal footbox provides more space for our feet to move freely without adding so much space that it increases the draft inside the bag.

The hood is contoured to the shape of your body, and it's easy to cinch tightly should you want to trap even more body heat when temperatures drop. The bag also includes a neck baffle, but we found the design to be a bit distracting. We have to tuck it in just right for it to prevent draft and provide a cozy feel, but if you move as much as our lead tester, you may find yourself having to adjust the baffle throughout the night. While the Magma 15 is a more affordable down sleeping bag option, it provides luxurious comfort through ample loft, supple materials, and custom sizing options.

Packed Size

The lightweight construction and highly packable size are just a few more reasons to select the Magma 15 as your next down sleeping bag. For most backpacking bag designs, the recommended range is 6 to 10 liters. That said, the Magma provides a compressed size (Medium Narrow) of just over 7 liters, making it one of the more packable options we tested.

The Magma 15 includes a super light stuff sack with your purchase, however, for those who want to maximize space inside their pack, we highly recommend purchasing an after-market compression stuff sack as you can easily reduce the packed size by almost half.

Features

The Magma 5 does a great job of including utilitarian features that maximize warmth and comfort without creating a heavy and bulky construction. We love the unique zipper path that opens up on the top of the chest rather than the side of the bag. The beefy main zipper is longer and more durable than most which is great for those cooler nights when you prefer ventilation over maximum warmth. It also features an anti-snag strip to prevent fabric from jamming into the zipper when opening and closing throughout the night.

While the Magma 15 does include an internal stash pocket that's big enough to stow our headlamp or eye mask, we wish it also included a zipper closure to prevent small items from falling out as we shift our positions throughout the night. It also includes a mesh storage bag as well as a minimalist stuff sack; however, we recommend purchasing an aftermarket compression sack for even more packability. Finally, we love that the Magma comes with a stash pocket to tuck away small items like a headlamp or contact case.

The stash pocket is conveniently located.   Credit: Trish Matheny

The two way zipper is functional and durable.   Credit: Trish Matheny

The stash pocket is easy to access but doesn't have a zippered closure.   Credit: Trish Matheny

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Should You Buy the REI Magma 15?

The Magma 15 is reasonably priced, especially considering its 850 fill-power waterproof goose down construction, complete with a durable water repellent finish. Although not the most affordable down sleeping bag that we tested, it provides a luxurious feel through its soft and supple interior as well as its highly customizable construction. Ample loft, thoughtful features, and durable zippers make this our favorite bag for everyday backpackers who are after a good nights sleep in the campground or the backcountry.

What Other Women's Sleeping Bags Should You Consider?

If the price tag is still a turn-off, we recommend the Kelty Cosmic Down 20, which is more affordable yet still provides similar warmth and comfort ratings.

If you want the best warmth and comfort with the lightest weight, options like the Western Mountaineering AlpinLite and the Feathered Friends Egret UL 20 are great. They both optimize thermal efficiency and comfort and pack down small.