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Osprey Exos Backpack Review

Osprey's new Exos 46 and Exos 58 backpacks are designed specifically for lightweight backpacking, and, at just over 2 pounds, set a new weight standard for an internal frame backpack with a built-in frame. Plus, they're durable and full-featured.

Hightly Recommended

Overall Rating: Highly Recommended

The new Exos 46 and 58 packs are a lightweight backpacker's dream come true. They set a new weight standard and are full featured. Every feature has been scrutinized for weight and functionality. I found a lot to like while testing the Exos; my nitpicks are few, and most will likely be corrected in the production model.

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by Will Rietveld |


Osprey Exos Backpack Review - 1
Before the storm. The new for spring 2009 Osprey Exos 46 (shown) and 58 packs will weigh just over 2 pounds and are full-featured.

We have previously reviewed the Osprey Aether and Atmos backpacks and found their feature set much to our liking, but their weights pushed our upper limits, and we could barely call them "lightweight." Osprey is solidly re-entering the lightweight backpack competition with its new Exos pack, which is a brand new pack series specifically designed to be lightweight. The Exos packs will be available in spring 2009 in 34, 46, and 58 liter volumes.



2009 Osprey Exos 46 and Exos 58


Built in internal frame, top loading with floating top pocket


Exos 46 is 2800 cu in (46 L)
Exos 58 is 3500 cu in (58 L)


Size M tested. Measured weight: Exos 46 2 lb, 3.3 oz (1 kg), Exos 58 2 lb, 6.5 oz (1.1 kg)
Manufacturer specification: Exos 46 1 lb, 14 oz (845g), Exos 58 2 lb, 3 oz (997g)

  Sizes Available

Unisex S, M, L

  Torso Fit Range

Small fits torso less than 18.5 in (47 cm), hip less than 31 in (79 cm)
Medium fits torso between 18.5 - 20.5 in (47-52 cm), hip between 30 - 34 in (76-86 cm)
Large fits torso longer than 20 in (51 cm), hip larger than 33 in (84 cm)


70d x 100d shadow-check and 160d x 210d window rip-stop

  Frame Material

6061-T6 aluminum, polycarbonate cross piece


Floating top pocket with zippered access and zippered mesh map pocket on the underside, stretch pocket for MP3 player or small GPS on shoulder strap, two mesh side pockets with top and side access, large front stretch-woven kango pocket, two mesh hipbelt pockets, full width front compartment under kango pocket with zippered access on both sides (one side on the Exos 46), two front tool holders (one on the Exos 46), four side compression straps, one top compression strap, two ice axe loops, two sleeping pad loops, Stow-on-the-Go trekking pole attachment, AirSpeed mesh backpanel, load lifters, adjustable sternum strap with whistle, ErgoPull hipbelt, 3L internal hydration sleeve with two hose ports

  Volume To Weight Ratio

79.3 ci/oz for the Exos 46, 90.9 ci/oz for the Exos 58 (based on 2800 and 3500 ci, respectively, and measured weights of 35.3 and 38.5 oz, respectively)

  Maximum Comfortable Load Carrying Capacity

30 lb estimated comfortable load for an average person carrying the pack all day

  Carry Load to Pack Weight Ratio

13.6 for the Exos 46 and 12.5 for the Exos 58 (based on 30 lb and a measured weight of 2.21 and 2.41 lb, respectively)


Exos 46 US$179
Exos 58 US$219

Suspension System and Features

Although the Exos was designed to be lightweight, it borrows a lot of design elements from Osprey's current Talon and Atmos backpack lines. Every component was optimized for light weight and functionality. It's rather amazing that a backpack with a built-in frame can be so light and at the same time have so many features (see the list in the Specifications section).

This review covers both the Exos 46 and Exos 58 backpacks, which differ mainly in volume. The feature set is nearly identical on the two packs, with only a few small differences.

Osprey Exos Backpack Review - 2
Views of the Osprey Exos 58 (and 46). The frontpanel view (top left) shows the pack's large front stretch-woven kango pocket and dual tool loops. The pack's AirSpeed backpanel (top right) is a trampoline type for increased ventilation. There is even a small pocket on one shoulder strap for an MP3 player. A side view (bottom left) shows the pack's large mesh pockets with top and side entry and narrow compression straps that will also attach items to the side of the pack. The top view (bottom right) reveals a zippered mesh map pocket under the top cap, top compression strap (orange), and drawcord closure.

Osprey Exos Backpack Review - 3
The new AirSpeed mesh backpanel on the Exos packs is not as deep as previous versions. The gap is about 1 inch, enough to provide good ventilation without interfering with pack volume or the pack's center of gravity. The peripheral contoured tubular frame is 6061-T6 aluminum.

Osprey Exos Backpack Review - 4
At first look, Osprey's BioStretch (mesh covered slotted foam) shoulder harness (left) and hipbelt wings (right) seem thin and inadequate, but the suspension system performed well with moderate loads (see my field testing section below).

Osprey Exos Backpack Review - 5
The peripheral tubular aluminum frame of the Exos is curved to wrap around the hips. Hipbelt wings and shoulder harness (see photo in previous panel) are attached to the backpanel mesh rather than the frame. This is not a design intended to carry heavy loads.

The Exos packs do NOT have an adjustable torso length like many larger Osprey packs. Rather, the shoulder straps and hipbelt wings are sewn to the backpanel and the only adjustment available is to lengthen or shorten shoulder straps and load lifters. Getting a proper fit is a matter of choosing the proper pack size. The Exos will be available in unisex sizes small, medium, and large (torso fit ranges are listed in the Specifications section).

Field Testing

During summer 2008, I tested both the Exos 46 and 58 on numerous backpacking trips carrying a wide range of loads. I tested the Exos 58 (58 liters) first, assuming it would be the optimum size for lightweight backpacking. However, using typical lightweight backpacking gear and loads in the 25- to 30-pound range, I was never able to completely fill it up. The Exos 58 has a lot of room! It has eight separate pockets, so a large portion of my gear fit in the pockets alone.

Osprey Exos Backpack Review - 6
The side mesh pockets on the Exos (left) have a side entry that enables a hiker to reach and replace a water bottle without taking the pack off. My favorite feature on the Exos pack is the large zippered compartment under the kango pocket on the frontpanel (right). The Exos 58 has zippered access on both sides, while the Exos has access on only one side. The pocket will hold numerous frequently needed items and make them easily accessible on the trail.

On one occasion, while volunteering for the Hardrock 100 Endurance Race, I used the Exos 58 to carry in 40-pound loads of supplies and food to a remote aid station, climbing 1000 feet over a three mile distance. The pack carried the weight just fine without popping a seam and transferred the majority of the weight to my hips, but I had to tighten the hipbelt really tight to keep it from slipping off my hips.

Although the Exos 58 carried moderate (25 to 30 pounds) loads comfortably, the heavier loads described above are beyond its comfort range, except for hikers with strong shoulders. Thus, for summer backpacking, the Exos 58 seems to have too much volume for its weight carrying capacity. On the other hand, the Exos 58 would be an excellent choice for winter backpacking, where more volume is needed for bulkier insulated clothing and gear.

Realizing that the Exos 58 was a bit too roomy for me, I tested the Exos 46 during the second half of the summer. Although 46 liters seems small, I found the volume to be closer to my needs for summer backpacking. On a six-day, 100-mile backpacking trip on the Continental Divide Trail, I was able to get all of my gear and eight days of food (31 pounds initial weight) into the Exos 46. It carried the weight comfortably enough, but I was happier when pack weight dropped under 25 pounds. It would help if the shoulder straps were a little wider to distribute the weight more.

My carry load tests closely agree with Osprey's recommended maximum carry weights of 20 to 30 pounds for both the Exos 46 and 58. Bottom line, the Exos backpacks are not designed or intended to carry heavy loads. My field testing confirmed that.

Osprey Exos Backpack Review - 7
Exos 46 on the Continental Divide Trail in Colorado. Because of its numerous pockets, the pack has more room than its 46-liter size would indicate. The Exos also carried well on day-length trips from a base camp (right).


The Exos is a brand new pack model, and it's remarkable that Osprey got most of the details right on the first try. In spite of its light weight, the Exos is loaded with features. I found it rather amazing that an internal frame backpack weighing slightly over 2 pounds can have so many features (including eight pockets!) and durable fabrics.

Osprey states "The Exos Series was designed with the knowledge that, in the long run, going light with a pack that has no suspension burns more energy than is gained by ounces saved." If they are referring to a frameless backpack, I personally would never carry 20- to 30-pound loads in a frameless pack. Granted, some frameless packs, like the GoLite Pinnacle and Jam2 are capable of carrying heavier loads more comfortably, but the updated Pinnacle and Jam2 for spring 2009 will weigh 2 pounds and 1 pound, 10 ounces, respectively - nearly as much as the Exos. My current pack of choice to carry 20 to 30 pounds is the Six Moon Designs Comet (27 ounces, $170 with stays) that has removable stays, but again the Comet weighs nearly as much as the Exos and does not have the feature set of the Exos. Needless to say, the Exos is now my pack of choice for carrying 20- to 30-pound loads.

However, the Exos is not quite perfect, and I have a few small issues to mention here, which hopefully will be addressed in the production pack.

  • The side mesh pockets are way too tight (see photo above), so they will not hold much when the main compartment is fully expanded
  • The sternum strap is adjustable, but I found its lowest setting to still be too high
  • The load lifter straps slip some; I needed to tighten them about twice a day
  • I didn't have much use for the sleeping pad straps on the bottom of the pack, and they catch on branches while bushwhacking (Osprey says they can easily be cut off.).

Overall, I'm very impressed with the new Osprey Exos backpacks. This is a pack designed from the ground up for lightweight backpacking, assuming you want a pack that has room for everything and plenty of organizing and convenience features. The Exos will carry a 20- to 30-pound load with comfort and is capable of carrying up to 35 pounds when necessary. Both packs have more room than their size (46 or 58 liters) would indicate, so be sure to take that into account when choosing which one to get.

What's Good

  • Sets a new weight standard for a built-in internal frame backpack.
  • Mesh backpanel provides ventilation and does not interfere with pack volume or center of gravity.
  • Lightweight, durable fabrics and frame material.
  • Large stretch kango front pocket is very handy for carrying a wet shelter or stuffing a jacket.
  • Contoured tubular frame is very lightweight, yet is capable of complete weight transfer to the hips.
  • Numerous pockets for organizing and convenient access.
  • Fits well (if you choose the correct size).
  • Comfortably carries moderate loads.

What's Not So Good

  • Torso length is not adjustable.
  • Side mesh pockets are tight when pack is full.
  • Load lifters slip and require retightening.
  • Sternum strap is too high.

Recommendations For Improvement

  • Lower the sternum strap.
  • Bellow the side mesh pockets and increase the size of the top opening.
  • Revise the load lifters so they don't slip.
  • Widen the shoulder straps to distribute weight.


"Osprey Exos Backpack Review," by Will Rietveld. (ISSN 1537-0364)., 2008-11-25 00:10:00-07.


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Osprey Exos Backpack Review
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Nicol Mackenzie
(nickima) - MLife

Locale: Monterey County, California
Osprey produced video on the Exos 46 on 12/08/2008 01:12:57 MST Print View

Osprey has produced a video to promote the Exos 46 pack:

I've been very happy with my Talon 44 and really like the shoulder straps and am excited to see them in the Exos series. This strap design has convinced me that a wide and stable shoulder strap can be lighter and more comfortable than the traditional thicker straps.

Eric Blumensaadt
(Danepacker) - MLife

Locale: Mojave Desert
Interesting on 12/08/2008 19:17:02 MST Print View

Looks like it's similar to my REI Cruise UL but with more pockets.(I added 2 REI aftermarket side pockets to mine.)

Osprey always has good quality. The 58 SHOULD be capable of regularly carrying 40 lbs. at that size.


Edited by Danepacker on 12/08/2008 19:17:56 MST.

/A .
(biointegra) - MLife

Locale: Puget Sound
Atmos v. Exos ride comparison? on 01/17/2009 19:21:28 MST Print View

I've enjoyed the Atmos 65 especially for mountaineering and was impressed at it's comfort with loads even hovering around 50 lbs while carrying photo/video equipment and climbing gear up to 17,000 feet last autumn. In fact, as counterintuitive as it seems, I found that the Atmos' suspension system and fit (subjective and key here) to be favorable to even some heavier packs, such as the Aether series, specifically designed for loads of that (un)nature.

The suspension system on the Exos 58 appears to be almost identical to the Atmos' - can anyone relay experience with both of these packs as a comparison of the comfort? In the Atmos, 40lbs did not seem like a stretch at all. 30-35 seemed like the sweet spot, as far as weight/comfort benefit.

I'll endeavor to do some 'sandbagging' at REI when opportunity befalls. If this performs within range of the Atmos, I can't imagine another pack that would have the same level of carry comfort/capacity for it's weight/volume range.

Joe Clement
(skinewmexico) - MLife

Locale: Southwest
Exos on 01/17/2009 21:30:07 MST Print View

I got my Exos 58 on Friday, but had to leave town and haven't gotten to play with it. Seems huge, makes me wonder if I hadn't screwed up.

(mountainwalker) - MLife

Locale: SF Bay Area & New England
58 or 46 on 01/22/2009 17:00:45 MST Print View

Hi Joe,

Have you had a chance to play with the 58? What do you think - too large? 58 or 46? From the excellent review it seems like the 46 would work exceptionally well for 3 season trips up to a week + day hikes.

Will's take: "Thus, for summer backpacking, the Exos 58 seems to have too much volume for its weight carrying capacity. On the other hand, the Exos 58 would be an excellent choice for winter backpacking, where more volume is needed for bulkier insulated clothing and gear."

For many years I've been using mid-size (2800-3200 cu in.) packs that work for both day hiking + week long 3 season trips + short winter trips - I like the versatility and nice to keep things simple and cheaper by only having to spend on one bag.

I'm willing to sacrifice a little extra weight for a pack with good suspension and features, like my Golite Infinity. The suspension could easily carry 40 lbs, even though I don't get to that. Light enough for DIAD hikes and strong enough and roomy enough for up to a week.

Edited by mountainwalker on 01/22/2009 17:18:06 MST.

(mountainwalker) - MLife

Locale: SF Bay Area & New England
Can the 58 be cinched down well enough for smaller volume? on 01/22/2009 17:08:25 MST Print View

Can the 58 be cinched down well enough to control a smaller volume load well?

Anthony Weston
(anthonyweston) - MLife

Locale: Southern CA
Exos 34 on 01/30/2009 17:37:38 MST Print View

Everyone said the Exos 58 was gigantic buy the 46, so I went even smaller and bought the Exos 34.

I own an Atmos 50 and the Exos 34 holds about the same amount of gear. I was able to fit the Bear Vault BV500 Bear canister inside the pack with 3 liters of water in the hydration sleeve but I had to shove the Platypus hydration water pack to the side but the pack didn't feel lopsided on my back.

I loaded pack with 35 lbs (stuff I would never take like 5 lbs of rice) and walked around the block.
The pack is designed to carry no more than 25 lbs but with all this room, I wanted to see if I could use the pack on a longer trek.

The pack is more fragile than I anticipated. I compared it side by side with the Atmos 50. The bag itself seems durable enough but with a big load running down the side of a hill, I could see the hip belt or shoulder straps developing a problem. Also netting on the airspeed frame although comfortable collapses and my lower back is against the pack something the Atmos doesn't do. The shoulder staps have just netting over foam which might be great in the heat but might snag going under logs and through brush.

The pack weighed 35 oz (large Exos 34) which is lb or so lighter than the Atmos 50. Because of my back, I can't carry a frameless pack. I'll try to post some photo's later, with a 12 lb base this pack might work for me on weekend trips as long as I'm disciplined and keep it less than full.

ben leace
(tanzer2250) - F
osprey exos v. ula circuit? on 02/09/2009 09:08:43 MST Print View

I appreciate the review and was wondering how these osprey packs compare to the ULA Circuit, in terms of space and firmness. The Circuit was just redesigned with a stiffer pad. An Aluminum stay can be added too.

I like the firm feeling of the Osprey Atmos 65. To me the extra weight has been worthwhile because of how well the load transfers to the hip belt and how stable the pack feels on my back. I am looking for a smaller pack that weighs closer to 2 lbs., but that still feels firm on my back and transfers weight well to the hip belt.

Pack weight will typically be in the 25-35 lb. range with food and water. Not ultralight, but getting better - I carry the tent, water filter and the cooking gear for two.

Darryl Romm
(Lyrrad) - F

Locale: Greater London
Re: Osprey Exos Backpack Review on 02/09/2009 12:25:37 MST Print View

This might be of interest to some

Osprey Exos Evaluation - The Results - Find out what five lucky OM members made of Ospreys brand new Exos 46 pack.

Here is the forum thread which is worth a read.

Edited by Lyrrad on 02/09/2009 12:29:02 MST.

Steve Parr
(srparr) - F

Locale: SE Michigan
Weight of the removable lid? on 02/11/2009 14:10:17 MST Print View

Osprey says the Exos pack lid is removable ... can anyone tell me what the lid weighs by itself? Preferably for a medium Exos 46, but either the 46 or 58 will give us an idea of how much weight can be easily removed.

I'm looking at the Exos and comparing it to the ULA Ohm. I like the ULA workmanship, and a medium Ohm with hydration sleeve & both hip pockets is spec'd at just shy of 25 oz. The Exos 46, with lid, comes in just over 35 oz (BPL tested weight).

The majority of this 10 oz difference seems to be the inclusion of the pack lid. I'd really like to know how much it weighs so I can compare the two packs.

UPDATE: I just finished reading through nearly 400 posts at the forum mentioned above. Apparently Osprey measures the capacity for the main bag only ... so the Exos 34 (2100 cu in) is perhaps a better comparison for the Ohm (which also has 2100 in the main bag).

The Exos 34 is spec'd to be 28 oz (these values come from the posted Exos owner manual ... the numbers vary between that and the Osprey webpages). But the max carry load is not as high as the Ohm & Exos 46.

Edited by srparr on 02/11/2009 17:47:01 MST.

Steve Parr
(srparr) - F

Locale: SE Michigan
Top lid is 3.7 oz on 02/13/2009 09:02:30 MST Print View

I just heard back from Osprey customer support, and thought others might be interested in the weight of the lid.

I also asked them about the correct weight of the Exos 46, and was told that the most accurate and up-to-date info is on the website ... which I take to mean that the production model came out a few ounces heavier than the prototype (documented in a downloadable Exos manual).

This means that the medium Exos 46 is 37 oz (and can go down to 33 oz with lid removed)

Since the medium Ohm is 25 oz (with hip pockets & hydration sleeve), I now need to decide if the ventilation frame is worth carrying an extra half a pound of pack weight.

Edited by srparr on 02/13/2009 09:04:01 MST.

Raymond Estrella
(rayestrella) - MLife

Locale: Northern Minnesota
re: Exos on 02/14/2009 12:18:48 MST Print View

Nice review Will,

As you know from the other site I have been a huge (and vocal) supporter of the Talon series. I got an Exos 58 last month and have already come to love it.

I could not use my Talon 44 on two trips in Yosemite last year because I could not fit a bear canister along with my normal loads. (I am not UL, just light.) The Exos is going to work great.

At first I thought I would miss being able to put my Platy Hoser behind the backpanel but after seeing how cool my back stayed with the Modified AirSpeed suspension I can live with it being inside the pack.

Fred eric
(Fre49) - MLife

Locale: France, vallée de la Loire
exos on 02/14/2009 13:49:49 MST Print View

Still waiting to get an exos 58.
The exos 46 has been available in Europe for a while, but couldnt find a 58 yet.

Atmos and Stratos were the only backpacks i tried that werent painful with my back, so cant wait to ge a lighter one.
Contrary to most i was never able to use teh space behind the mesh to store a platy, i cannot bear the pressure it adds on my spine.
So a smaller gap between the mesh is all benefit for me , i dont use it, the load will be closer to my back, and the bag should be easier to fill.

Lex Rogerson
(lexlaw) - F
Exos 58 on 03/04/2009 18:07:02 MST Print View

The Gear Issue of Backpacker Magazine, while overall quite positive about this pack, says the shoulder straps need frequent tightening. Can anyone who has used the pack either confirm or rebut this notion?

Richard Sullivan
(richard.s) - MLife

Locale: Supernatural BC
Re: Osprey Exos on 04/05/2009 12:38:34 MDT Print View

According to Osprey, the self-loosening strap problem was resolved for production. They have also told me that the volume spec is for the main bag only.

Just weighed my Exos 58 Size L and it is 2 lb 9.9 oz, right on spec. The top pocket can be removed to save 4.4 oz.

Lynn Tramper
(retropump) - F

Locale: The Antipodes of La Coruna
Re: Re: Osprey Exos on 04/06/2009 14:14:40 MDT Print View

Also note that the Exos 58 in a size large is actually a 61 litre pack. I tested one of these last Saturday with a full 35lb load to see if it really could a) hold that much and b) carry it comfortably. The answer to both questions was a big YES. But if it were my pack, I would be chopping off a lot of the excess straps and doodads on it, not to mention replacing the mesh pockets with something less prone to snagging.

/A .
(biointegra) - MLife

Locale: Puget Sound
Size M weights: on 04/06/2009 15:39:58 MDT Print View

I just picked up a size M Exos 58 from REI. The actual measured weights are as follows:

Pack.....35.7 oz.
Lid.......4.3 oz.
Total....40.0 oz. (2 lb. 8 oz.)

~ excellent build quality and features
~ a few excess straps and lengths - i.e. dual ice axe loops, waste straps long (perhaps 2 oz. worth max)
~ seems to fit/function very similarly to the Atmos
~ innovative minimal buckles (1/4" fastex buckles!)
- most comfortable non-rigid waist belt i've used (like Atmos)
- compresses quite small - should be ok for carry-on
- in order to utilize outer pockets best, don't pack main bag completely full
- compression straps stabilize load well for moving fast on varied terrain

I wonder if a large zpacks cuben-fibre pack cover will fit?

Edited by biointegra on 04/06/2009 15:44:31 MDT.

Kevin Yang
(kjyang) - F
Exos 46 on 05/11/2009 00:36:11 MDT Print View

Just got a Medium Exos 46 at REI. Total weight of the pack is 37.0z. The removable lid weighs 3.75oz.

Fred eric
(Fre49) - MLife

Locale: France, vallée de la Loire
cape wrath trail :1 / exos 58 :0 on 05/11/2009 05:50:18 MDT Print View

Just back from the underwater south cape wrath trail :)
got rain close to 24/24 for one week

as for my exos 58 pack :exos

i tried to put the "O" back in place but it wouldnt hold for long.

Diplomatic Mike

Locale: Under a bush in Scotland
Fred on CWT. on 05/11/2009 06:43:52 MDT Print View

I was thinking of you last week Fred. I had read on here you were doing the CWT. I was out for one night in that weather, and that was enough. I can't remember a worse week for rain. Like you said, 24/24 for a week. I know of one person who called out SAR because they were soaked and stranded by high water levels in the rivers. They were going down with hypothermia.

You'll be happy to know the weather is sunny and beautiful now! :)