How to Choose Sleeping Bags for Backpacking
REI Co-op Magma 15 Sleeping Bag - Men's
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Superlight, very compressible and insulated with water-resistant, premium 850-fill-power goose down, the REI Co-op men's Magma 15 sleeping bag delivers our best warmth-to-weight ratio.
Shop newer versionKey Details
Fill
850-fill-power goose down (bluesign approved)
Temperature Rating (F)
16 degrees (F)
- Designed with generous knee and foot space and a fitted silhouette that delivers the most efficient warmth-to-weight ratio in the REI Co-op brand sleeping bag line
- Downproof Pertex® shell, water-resistant 850-fill-power goose down and supple 15-denier lining combine to provide lasting coziness and a supersoft feel
- Down is bluesign® approved
- Trapezoidal footbox keeps feet comfy; a toe box baffle positions downward to provide warmth
- Variable baffle spacing locates and stabilizes the down fill, delivering high thermal efficiency and reducing weight
- Zipper cover and internal antisnag strip combine for easy zipping; a hybrid zipper path provides easy access along shoulders and torso
- Contoured hood retains warmth while providing space for a low-profile pillow; 2 different hood drawcords allow internal adjustment to avoid heat loss
- Insulated yoke fills neck and shoulder gap to prevent heat loss
- Includes a stuff sack for packing and a roomy mesh sack for breathable storage
- REI Co-op brand is certified to The Climate Label; we actively fund efforts to reduce carbon emissions across our business and support climate projects around the world
- Contains materials that meet the bluesign® criteria
Imported.
Temperature ratings are intended as a guideline to help you compare products, rather than a guarantee of warmth, since many different factors contribute to your comfort while you sleep. Our backpacking bags are rated for temperature according to an independent testing protocol: International Organization for Standardization (ISO) 23537. Testing is based on a person wearing one base layer and a pair of socks, sleeping on an insulated surface with a minimum R-value of 5.38.
Each bag then gets 2 ratings: the Comfort rating is the lowest temperature at which the bag will keep the average "cold sleeper" comfortable, and the Lower Limit rating is the lowest temperature at which the bag will keep the average "warm sleeper" comfortable. For REI Co-op brand nongendered sleeping bags, we provide an overall temperature rating that falls between the Comfort and Lower Limit ratings.
View the REI Co-op Magma Product LineView all REI Co-op Backpacking Sleeping BagsEach bag then gets 2 ratings: the Comfort rating is the lowest temperature at which the bag will keep the average "cold sleeper" comfortable, and the Lower Limit rating is the lowest temperature at which the bag will keep the average "warm sleeper" comfortable. For REI Co-op brand nongendered sleeping bags, we provide an overall temperature rating that falls between the Comfort and Lower Limit ratings.
| Best Use | Backpacking |
|---|---|
| Tested Lower Limit | 16 degrees (F) - ISO |
| Tested Comfort | 28 degrees (F) - ISO |
| Temperature Rating (F) | 16 degrees (F) |
| Temperature Rating (C) | -8.9 degrees (C) |
| Ultralight | Yes |
| Shell | Pertex 15-denier ripstop nylon (bluesign approved) |
| Zipper Location | Left |
| Insulation Type | Down |
| Water-Resistant Down | Yes |
| Fill | 850-fill-power goose down (bluesign approved) |
| Lining | 15-denier ripstop nylon (bluesign approved) |
| Sleeping Bag Shape | Mummy |
| Shoulder Girth (in.) | 63 inches |
| Hip Girth (in.) | 57 inches |
| Stuff Sack Size | 7.5 x 15 inches |
| Stuff Sack Volume | 10.9 liters |
| Gender | Men's |
| Sustainability | Contains materials that meet the bluesign® criteria From a Climate Label Certified brand |
Buying Advice
Better gear is built together
From feedback to field testing, all of our gear is dialed-in by REI Co-op members. Their adventures informed every stitch and detail—making for better, longer-lasting gear.
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Most Helpful Favorable Review
Cutting Weight
Coloradicaladdict6 years ago
Love the new 15 degree bag and everything it has to offer. The zipper is especially nice! I tested this at 28 degrees with just a base layer and I was roasting. The one caveat I am a little concerned about is that my torso was super toasty, but my legs were just warm. Wonder how this will do in the lower temps, but I mostly bought it for a 3 season bag. One piece of advice is to use a pad with a high R-value. I use to buy 0 degree bags and would freeze because I did not have a pad or bought a cheap one with a low R value. I just see people giving 0-15 degree sleeping bags bad reviews because they are cold. Pad has everything to do with this!
Coloradicaladdict
Denver Colorado
78 people found this review helpful
Most Helpful Critical Review
Degraded after a month on PCT
Shoey6 years ago
I'm currently thru hiking the PCT, using the Magma 15 with a Thermarest Neoair and sleeping in a Big Agnes Copper Spur.
This bag was brilliant the first ten days, it is super light and the materials soft to touch.
However, slowly the down has become clumpy and/or flat in parts of the bag. I have tried relofting the down by airing the bag out in the sun on a daily basis, but the down fails to retain any loft and remains unevenly spread within the bag. When I have used the bag in below freezing temps on San Jacinto and Baden Powell, I had to layer up wearing my base layer, two pairs of socks, rain pants, fleece, and puffy in order to stay warm enough. While there appears to be many happy punters with this bag, I regret not spending a bit more and getting a higher quality bag. I will look at returning this bag to REI if possible.
Shoey
Tehachapi, CA
111 people found this review helpful
Customer Images
Cmorrell
Montana
Not durable
2 years ago
I bought this bag for a season of camping & trail work. After the first summer having it, the neck wrap piece started to rip & I lost a lot of down, and the tightening strap for the head hole tore & came loose entirely. I patched it up, washed and fixed the bag for my second season. It had lost so much down that I needed a full blanket inside to keep warm during the summer months in Montana. By the time I had finished my second summer with the bag, the zipper had broken off entirely, it doesn’t zip & it’s littered with holes. It is very light. If you have an exorbitant amount of money to spend on gear for one thru-hike, it’s a fine bag. If you want something that will last, do not buy this.
Age:25–34
Weight:125–150 lbs.
Height:6'0"
No, I do not recommend this product
Zdub94
Broken zipper, no hope for replacement
1 year ago
I bought the Men's long 15° bag 2 years ago. After using it for 2 summers, the zipper broke. I was using the bag normally, and it was adjusting wall inside the bag when the zipper split open. Now, these zipper won't stay closed whenever I try to zip or unzip the bag, so it's now useless. A sleeping bag like this for the price its at should be well constructed and last several years of standard use. REI's one year return policy means I can't return the bag, and they have no additional warranty or options for repair. For a higher price item like this that is suppose to last several years, it's absurd they don't have additional protections or a longer warranty. I was looking for a bag that would serve me well for several years, but now my bad is unusable and I have no options through REI for exchanging or getting it repaired under a warranty that it should have. If you're looking for a good, sturdy bag that can stand up to camping or backpacking, this isn't it. Be prepared to lose your money and to have to find another sleeping bag in 2 years.
Age:25–34
Weight:225–250 lbs.
Height:6'1"
No, I do not recommend this product
Coloradicaladdict
Denver Colorado
Cutting Weight
6 years ago
Love the new 15 degree bag and everything it has to offer. The zipper is especially nice! I tested this at 28 degrees with just a base layer and I was roasting. The one caveat I am a little concerned about is that my torso was super toasty, but my legs were just warm. Wonder how this will do in the lower temps, but I mostly bought it for a 3 season bag. One piece of advice is to use a pad with a high R-value. I use to buy 0 degree bags and would freeze because I did not have a pad or bought a cheap one with a low R value. I just see people giving 0-15 degree sleeping bags bad reviews because they are cold. Pad has everything to do with this!
Yes , I recommend this product
Chris
Get the women's bag
3 years ago
Could have been great but felt it was just short of having enough down. Tons of cold spots and the bag never felt super lofty. I ended up upgrading to the women's long. For the same price you get an extra 8 ounces of down which increases the t-limit from 16 degrees to 3 degrees. Wish REI would have just given the men's bag more fill and called it a 0 degree.
Age:35–44
Weight:150–175 lbs.
Height:5'10"
No, I do not recommend this product
Bike Touring Backpacker
Sacramento ,Ca
Great Overall Light Down Sleeping bag
4 years ago
Had concerns of the warmth performance after reading some of the previous reviews before I bought a week ago and took advantage of the REI sale on this Magna. Took it out 4 days ago in South Lake Tahoe Sierra and Kept me warm while only wearing lightweight thermal underwear. Impressive since I had the rainfly off the tent with plenty of cool night air coming through the netting. If, I was going to be packing in the high Eastern Sierra peaks or up in Wyoming's Wind River on a cold night, would put the fly on and wear middle / heavy weight thermals. This bag is 5 out of 5 for being extremely Lght and No Bulk while doing its job, which for backpacking and bike touring is a major concern for me.
Age:65–74
Weight:150–175 lbs.
Height:5'7"
Yes , I recommend this product
Hungry Wolf
SC
Amazing Warmth-to-Weight Ratio
5 years ago
Crossed the highest peak (Mt. Rogers) in VA on the AT with this one in Jan. Morning temp. was 15F, wind 20mph. I had to wear my smartwools head to toe in the bag but was comfortable through the night. I have the Magma 10 from a couple years ago (only difference is 2 more oz of down fill.) The baffles are nice and big and kill drafts well. Easiest bag to zip I have ever had. Impressive loft and super compfy on the skin. I am an very cold sleeper and prefer over kill on my bag. This one does the job. Now to put the miles on it.
Anonymous
Malvern, PA
Down migrates leaving cold patches
3 years ago
Love everything about the bag except its not warm enough. Like the size, the weight, the way it stores, the zipper, the hood..... However, the bag was not even close to warm enough for me vs. its stated comfort level in the 20s. As a side sleeper, I found it was not good even in low 40s. I observed that the down slides along the circumferential baffles from the high points of the bag (i.e. what is touching your leg, hip, shoulders, etc.) and leaves the inner and outer layers touching directly at the high points of the bag. That's where I felt the cold. I tried everything to solve this - storing the bag loose between nights, vigorous down redistribution, redistribution of down part way through the night, careful movements....Nothing worked so sadly I ended up returning it. It might work better for a back sleeper? In reality, nothing really keeps the down at the top of the bag except the density of the down below it and the friction of the baffles. Something is not quite working right here.
Age:45–54
Weight:150–175 lbs.
Height:6'4"
No, I do not recommend this product
Sierra Madness
Terrible water resistance, but generally warm
3 years ago
Bag gets seriously wet when dealing with minor moisture challenges, for example - tent walls drips that are unavoidable in certain conditions. Implying the shell is moisture resistant in any way is misleading to me. BUT, I’ve put lots of miles on mine. Hiked JMT, some PCT sections, and lots more with it. I freeze at night (cold sleeper), but solved that problem by using bag more like a quilt with a Thermarest Reactor liner. Personally, if REI solved the moisture challenge, it would be perfect, but this minor oversight of good moisture resistance creates challenges in colder weather where you can’t dry bag between nights.
Age:55–64
Weight:200–225 lbs.
Height:6'1"
No, I do not recommend this product
Bearded Wonder
North Canton, OH
It is snug for big fellas
3 years ago
I am 5’ 10”, 250 lbs, and about 52” around the chest and shoulders. This bag worked on my most recent trip, but it was a bit snug. I toss and side sleep, this bag was snug enough to wake me up at just about any movement. I was sufficiently warm down to 25F on several test sleeps in the winter, and it was just as comfortable up to 60F at night during my most recent section hike. If I was not a mover at night, or a bit slimmer, this would be an amazing bag. I plan on bequeathing this to my wife and looking for something a bit bigger. All around it is a solid and amazing product!
Age:35–44
Weight:225–250 lbs.
Height:5'10"
Yes , I recommend this product
randyran
Texas
Solid bag
5 years ago
Went backpacking on a few loops in Colorado, bag was great, paired with a nemo vector pad. I had plenty of room for side sleeping and was comfortable in low 30’s in boxers and shirt, even opening one side up a bit at times due to heat. One night when sleeping with family one pad, older big Agnes, had failed so I slept on the ground, no pad I slept comfortable. Bag packs down well, I use a size small sea to summit compression sack. I originally purchased a regular, I am 6’ and I felt like my feet were going to rip the end when moving around, so I opted for long, huge difference on comfort for minimal extra weight. The bag is not cheap, but I want my gear to be light and perform so the cost was worth it.
Age:35–44
Weight:175–200 lbs.
Height:6'0"
Yes , I recommend this product
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