REI Magma 10 sleeping bag.

REI Magma 10 sleeping bag.

Three-Season Sleeping Bag
REI Magma 10 and Magma 17
$349, 1 lb. 13 oz. (regular) 10° F
Sizes: men’s and women’s regular and long

On the last night of a 40-mile May backpacking trip in Utah’s Dark Canyon, a friend and I slept out under the stars and a heavy dew fell during the night. But I didn’t notice it until after waking up, seeing the droplets covering everything around me, and sticking a hand outside to feel my bag’s wet shell. Inside my REI Magma 10—which appeared to lose none of its loft, despite its shell getting soaked—I stayed warm and dry. That was a clincher moment in convincing me of what a super value REI’s men’s and women’s Magma sleeping bags represent in high-quality, water-resistant down bags.

REI Magma 10.

REI Magma 10.

I slept comfortably in this mummy bag for three May nights backpacking Utah’s Dark Canyon, including one night at over 8,500 feet when the low dipped into the 30s Fahrenheit and I left the rainfly off my tent and wore only underwear and a long-sleeve top. (A tent with its rainfly on is usually several degrees warmer than the outside air; but it doesn’t trap heat with the rainfly off.) The bag warmed up within a minute after I crawled inside, and I closed the bag and hood up completely. I also used it on two nights in the 40s Fahrenheit on a 39-mile, mid-September backpacking trip in Wyoming’s Wind River Range, including a night when the bag’s shell got damp from heavy rain blowing into the tent before I woke up and closed the vestibule door (which I’d left open because it wasn’t raining when I fell asleep).

It was more than warm enough for the temperatures I experienced; most nights, I didn’t even have to zip it up completely or put up the hood. I think the EN (European Norm) comfort rating of 22° F and limit rating 10° F for the men’s Magma 10, and 17° F and 3° F for the women’s Magma 17, are reliable measures for people who don’t get cold too easily; those who do may prefer to use these bags in temps at least 10 to 15 degrees warmer than those ratings. I stayed dry when the bag got wet thanks to its 17.6 ounces (500 grams) of water-resistant 850-fill goose down feathers (in the men’s regular), and a down-proof Pertex shell that let no feathers leak out and repelled moisture. The shell dried quickly in the morning sunshine, thanks in part to its black color.


Hi, I’m Michael Lanza, the creator of The Big Outside, recognized as a top outdoors blog by USA Today and others. I invite you to get email updates about new stories and gear giveaways by entering your email address in the box in the left sidebar, at the bottom of this post, or on my About page, and follow my adventures on Facebook, Twitter, and Instagram.


The bag’s generous dimensions—72 inches long, 60 inches of girth at the shoulders, and 57 inches at the hips (in the men’s regular)—allowed me to easily pull on pants while inside it. The warm, contoured hood’s two drawstrings let me adjust the fit as snugly as I wanted around my face, and it has space for a small, inflatable pillow, while an insulated neck yoke keeps cold air outside. The horizontal baffles with variable spacing prevent the down from migrating, for thermal efficiency and to help minimize weight. The trapezoidal foot box provides comfortable space and keeps feet warm. The zipper moves smoothly, without snagging, thanks to a zipper cover and an internal anti-snag strip. The stuff sack measures 15×7.5 inches (eight liters), but a compression sack can squeeze this into a slightly smaller package.

REI has built a successful business model based partly on offering quality products at value prices. With the men’s Magma 10 and women’s Magma 17 sleeping bags, it has done that again.

BUY IT NOW You can support my work on this blog by clicking either of these links to purchase a men’s REI Magma 10 at or a women’s REI Magma 17 at


Tell me what you think.

I spent a lot of time writing this story, so if you enjoyed it, please consider giving it a share using one of the buttons below, and leave a comment or question at the bottom of this story. I’d really appreciate it.


See all of my reviews of sleeping bags that I like and all of my reviews of backpacking gear, and my articles “Pro Tips for Buying Sleeping Bags” and “10 Pro Tips: Staying Warm in a Sleeping Bag.”

NOTE: I tested gear for Backpacker Magazine for 20 years. At The Big Outside, I review only what I consider the best outdoor gear and apparel. See categorized menus of all my gear reviews at The Big Outside.

—Michael Lanza

This blog and website is my full-time job and I rely on the support of readers. If you like what you see here, please help me continue producing The Big Outside by making a donation using the Support button at the top of the left sidebar or below. Thank you for your support.


The Big Outside is proud to partner with sponsor, who supports the stories you read at this blog. Find out more about them and how to sponsor my blog at my sponsors page at The Big Outside. Click on the ad below for the best prices on great gear.