REI Co-op Magma 15 Sleeping Bag Review
Inclusive size range, actually a 10 degree bag
Hold onto your geese, because a size medium REI Co-op Magma 15 Sleeping Bag is stuffed with 23.3 oz of 850 fill power down. That’s shockingly generous for a 15° bag, which is why it’s actually rated to 10°. Shop now.
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- Weight: 35.6
- Price: $429
- Down: 850 fill power RDS hydrophobic goose down
- Fill Weight: 23.3 oz
- Fabric: 15D Ventum Ripstop Nylon
- Down Vol: 19805 in³ | Down Vol/oz: 556 in³
- Estimated Comfort: +20 F
- Pros: Warmer than rating implies. Massive quantity of down fill. Decent value. Recycled materials. Interior pocket. Inclusive sizing. Larger sizes are not more expensive.
- Cons: Midweight. Likely too warm to be your daily driver. 15d fabric is slightly overkill.
Construction & Features
While we’ve grouped the REI Co-op Magma 15 Sleeping Bag into the 20 degree class for consistency within this buyer’s guide based on its namesake number, it has almost 50% more down than average, and 25% more than the other 15° models. That’s because it’s rated to 9°. So why is it called the Magma 15 and is this helpful or confusing?
Traditionally, the number in the name of a sleeping bag is its ISO tested lower limit, which corresponds to the lowest temperature in which someone sleeping in it could reasonably fall asleep. For women’s specific bags, more insulation is required to achieve the same rating due to the fact that women sleep slightly colder. This is illustrated in how the Sea to Summit men’s spark 18 has the same amount of down insulation as the women’s flame 25.
So it would appear that, despite this being a unisex design (which usually uses the unisex temp rating system), REI applied the women’s temp rating system to ensure everyone who uses it would be comfortable. Despite the unconventional approach, the extra down is very much welcome. At least nine out of 10 sleeping bag complaints are “it’s too cold” and not “it’s too hot.” So even if it’s confusing and bucks industry naming convention trends, the end result will likely please customers on the whole.
So we have a nice warm bag, but what else about it is noteworthy? We nod to the inclusive sizing, with every possible combination of short/medium/long X narrow/medium/wide. All bodies are welcome to soak in the Magma! We also note that they have not cranked up the price on longer/wider bags, which are much more expensive to manufacture, instead offering an average price across the board. This keeps things nice and simple, but it’s a bit of a bummer for smaller people who are paying for more materials than they’re not using.
Lastly, a few other features. The 15d recycled nylon shell fabric is fine, but would have offered superior ultralight performance at 10d. And speaking of getting cozy, that cinchable hood with insulated neck yoke is ultra niiiice.
REI Co-op Magma 15 Sleeping Bag Review Verdict
View the REI Co-op Magma 15 as a 10° bag and you’ll have a better grasp on what it’s offering, why it’s as heavy as it is, and the overall appeal. As such, the combination of generously filled baffles and reasonable price point make this a pretty tempting offer, but likely a better bag for spring and fall than summer.
Compare this to more great ultralight sleeping bags.
