Gear Review: Osprey Exos 58 and Eja 58 Ultralight Backpacks

Ultralight Backpack
Osprey Exos 58 and Eja 58
$240, 58L/3,539 c.i., 2 lbs. 11 oz. (men’s medium Exos)
Sizes: men’s Exos S-L, women’s Eja XS-M

It’s difficult and sometimes dangerous to improve on a piece of gear that’s nearly perfect in its simplicity and functionality. So when Osprey rolled out the redesigned Exos for 2018, along with a women’s version, the Eja, with some changes to this popular model—which became an ultralight pack archetype when it was introduced in 2008—I immediately wanted to see whether the changes represent an improvement. Taking it on a six-day, 94-mile hike on the Continental Divide Trail through Glacier National Park, I found definite improvements—including that it carries better than the previous iteration—and I think some backpackers may miss one convenient feature that’s absent from the updated pack.

For starters, Osprey finally made a critical update to its ultralight pack line, launching a women’s version, the Eja, with the same design as the Exos. Both models come in three torso sizes and three capacities (38L, 48L, and 58L). My 18-inch (46cm) torso falls on the cusp between a small and medium in the Exos 58; I chose the medium and it was comfortable with 30 pounds in the pack.

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Osprey Exos 58 backpack.
Osprey Exos 58 front.

I had no trouble fitting my ultralight gear—including one luxury, a collapsible camp chair (the 17-ounce Helinox Chair Zero)—and food for six days inside the Exos 58 without overloading it. While I see the Exos 48 as strictly for backpackers taking short trips with a very minimalist kit, and the Exos 38 as basically a large daypack or possibly useful for extremely ultralight backpacking, the Exos 58 certainly has the capacity for weeklong trips and ultralight thru-hiking.

With an empty weight just a few ounces over 2.5 pounds, the Exos carries 30 pounds or more comfortably, thanks to the fixed (non-adjustable) Lightwire alloy perimeter frame with a stabilizing plastic cross strut. Like its predecessor, the frame has slight flex along its vertical and horizontal axes, and the frame’s curved shape transfers much of the pack weight onto your hips, where you want it. The redesigned frame is a couple of inches taller and has more of a bell shape than the previous version of the Exos, which helps focus the load more directly onto the hips—an improvement in comfort that’s noticeable, particularly on longer days or when you’ve loaded the pack to its weight capacity.

Like comparably minimalist suspensions, this one can generate a little bounce in the load, primarily when the pack weight exceeds 25 to 30 pounds. It’s not very noticeable, though, and basically unavoidable unless you get a pack with a more substantial suspension, which means significantly heavier.

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Osprey Exos 58 harness and back panel.
Osprey Exos 58 harness and back panel.

The trampoline-style back panel with side ventilation keeps the packbag off your back, allowing air movement through that gap. I noticed the cooling effect on long climbs to mountain passes under a warm sun in Glacier. The shoulder straps made of highly breathable, perforated foam are improved over the previous version, made slightly wider near the top, with the foam extending farther down toward the armpit.

Perhaps the biggest design change appears in the hipbelt. While still made of breathable, perforated foam, it replaces the zippered pockets of the previous Exos with a cutout that improves breathability, and a different wrap and weight distribution intended to complement the frame’s increased length and pronounced bell shape.

Osprey gave me this explanation for the hipbelt redesign that eliminates the hipbelt pockets: “The decision to remove the hipbelt pockets from the new Exos/Eja was not based on either cost or weight savings but rather a small sacrifice in the name of comfort. During the design process of Levity/Lumina, we found that this style of pack carried much better and was significantly more comfortable with this contoured shape that is wider at the bottom. This bell shape gives a better wrap around the hip and really adds to the comfort. With the bottom of the pack being wider, the hipbelt is much shorter and there is not room for a pocket that would be worthwhile. Our design ethos puts fit and comfort first and we are sometimes faced with the decision of features vs. fit/comfort. Fit and comfort will almost always win that battle.”

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Osprey Exos 58 hipbelt.
Osprey Exos 58 hipbelt.

As I wrote above, I think the redesigned pack carries a bit more comfortably than its predecessor. A friend with me in Glacier who has been a contented owner of the previous Exos 58 for some years told me, “I think I’d miss the hipbelt pockets.” I’ve always been a fan of hipbelt pockets on a pack. But in reality, the ease with which you can reach into the side pockets while wearing the new Exos—and thus keep snacks in them—meant I didn’t really notice not having the hipbelt pockets on our Glacier hike. I agree with Osprey’s decision that comfort should trump convenience in this case.

Osprey kept other smart details in the new Exos and Eja. The lid pocket is removable, to reduce pack weight by 4.5 ounces when unneeded, and it has good space for a pack in this category, plus a spacious, zippered valuables pocket on its bottom side. A fixed flap clips over the top-loading main compartment when you don’t bring the lid. But the lid is not extendable—arguably a good thing, because you don’t want to overload this pack, and you especially don’t want to make it top-heavy. (You also don’t want to make a pack with a trampoline-style back panel front-heavy, which can tip the weight away from your back, making the pack pull uncomfortably against your shoulders. See my video on how to properly load a backpack.)

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That said, the voluminous, stretch pockets on the front (large enough for a wet rainfly) and both sides (which fit a liter bottle with space to spare) do allow you to begin a trip with the Exos or Eja loaded beyond recommended capacity (and ideally eat into that load to reduce it within a day).

The new Exos/Eja also retain a favorite feature of mine, the trekking poles attachment on the left shoulder strap, useful for freeing your hands to shoot a photo on the move or scramble steeper terrain. These packs have standard features like ample side compression and external attachments for gear, including a single ice axe. The redesign eliminated the stretch-mesh pockets on each shoulder strap for bars or gels. The lightweight, 100-denier, high-tenacity nylon pack fabric in the bag and 210-denier high-tenacity nylon on the bottom compares to many packs.

They also come in the smaller Exos 48 and Eja 48 ($220, 48L/2,929 c.i., 2 lbs. 8 oz.), Exos 38 and Eja 38 ($200, 38L/2,319 c.i., 2 lbs. 5 oz.) is sized for use as a large daypack or for extremely ultralight backpacking.

As a side note, Osprey also introduced what it’s calling “super ultralight” packs in 2018, the men’s Levity 60 and women’s Lumina 60 ($270, 1.9 lbs.), which Osprey says carry up to 25 pounds, and the smaller Levity 45 and Lumina 45 ($250, 1.8 lbs.). Osprey cautions that these packs are definitely for committed ultralighters—for lighter loads than the Exos/Eja. I hope to test and review one soon, but I agree that they appear to be designed strictly for backpackers—primarily thru-hikers—who are carrying extremely minimalist kits.

Testing the Osprey Exos 58 in Glacier National Park.
Testing the Osprey Exos 58 in Glacier National Park.

Osprey Exos 58 and Eja 58


The Verdict

For ultralight backpackers who may carry 30 pounds or more and need a pack that can handle trips or thru-hiking sections of up to a week—while being light enough for shorter trips—the Osprey men’s Exos 58 and women’s Eja 58 are not the lightest options on the market, but are leaders in terms of comfort and design, and available at a competitive price.



You can support my work on this blog, at no cost to you, by clicking any of these affiliate links to purchase any men’s Osprey Exos backpack at or, or any women’s Osprey Eja backpack at or, or one of the Levity or Lumina packs at the links in the above paragraph.

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See all of my reviews of backpacks, ultralight backpacks, backpacking gear, and ultralight backpacking gear at The Big Outside. Click here to read my review of the previous version of the Osprey Exos 58.

See also my “Top 5 Tips For Buying the Right Backpacking Pack,” and my stories “Gear Review: The 10 Best Backpacking Packs” and “Ask Me: What’s the Best Ultralight Thru-Hiking Backpack?

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 of my gear reviews at The Big Outside.

—Michael Lanza


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