Lightweight walking is a minimalist pursuit involving a delightful trade-off between the weight, strength and cost of equipment.

Many features are simply dispensed with in this quest, fabrics are lighter, straps thinner and shorter: every gram and millimetre is considered and accounted for. The result is lower pack weight, giving the bushwalker the ability to travel further, easier and faster, with less wear and tear on the body.

Osprey is a respected American pack manufacturer of over 40 years standing, who offer a vast and sometimes bewildering range of packs. Osprey says their newly updated Exos models are ultralight, and ‘great for weekend trips and way further’. The Exos 48 sits between the 38 and 58-litre models and would be the popular size for general lightweight hiking.

Osprey Exos key features:

The standout feature of this bag has not been seen on backpacks since the 1960’s, and it constitutes the major success of the design. It is what gives this pack an outstanding load carrying ability and strength.

Exos has a full external steel frame. Yes, that’s right, the heart of this bag is formed from two metres of 4mm diameter high tensile solid steel, which curves and loops around the entire perimeter of this backpack. While it contributes about 200 grams to the pack weight, the peace of mind afforded over alternative carbon fibre or aluminium alloy frames is immeasurable. Full credit to the designer for using a durable, strong material in an innovative way to form the rock-solid foundations of this bag.

Osprey Exos 48 Backpack Review

This frame supports a tightly sprung ‘trampoline’ back pad which provides comfort without the weight of conventional padding. No more sweaty backs – for superb ventilation the trampoline panel is riddled with more holes than an Anzac’s hat.

The Exos pack has discrete reflective details and two-tone colours. The attractively shaped bag has a drawstring closure covered by a flap, plus an optional floating lid. Exos has many features which are often not found on such a lightweight pack:

  • Load lifters: a buckle on the top of each shoulder strap to cinch the load in closer to your back for more stability.
  • A central internal compression strap to squeeze down the load before snapping the lid on.
  • Two large side pockets capable of each holding two 1.25 litre water bottles. Yes… 5 litres outside.
  • Large front pocket for bulky or wet items such as a rain coat or tent fly.
  • “Stow-on-the-Go” pole storage loops. I don’t use sticks but if this feature prevents walkers stopping suddenly and frequently in front of me to stow their sticks, then that is a good thing.
  • Full water bladder system: internal sleeve with hanging buckle, exit port and tube routing loops.


Indicative of Osprey’s attention to detail is a small eyelet to allow any spillage or sweating of the water bladder to drain externally, rather than inside the pack.

Other expected features are there: ice axe loop (with a quick release bungee lock), sternum strap whistle, side compression straps.

Amusingly, Exos comes with a strap to secure a closed cell foam mat horizontally to the bottom. This might be a style nod to the retro frame, but fortunately it is readily removed. The side compression straps can be easily reconfigured for winter campers who use closed cell foam, or to secure other things such as snow shoes to the front of the pack.

There are however some features which are surprisingly missing:

  • Hip belt pockets.
  • A fixed, zipped external pocket.


In addition to the top flap, there is a removable top lid of about 5 litres capacity. The removable lid has two pockets: one inside and one outside. There is however only one set of buckles, so you fasten either the flap or the top lid. I found the whole affair fussy: but if you leave the top lid off, you have nowhere readily accessible and secure to put your small items.

The removable lid component is too small to convert the pack from a weekender to longer expeditions of say a week or more. This puzzling uncertainty is in contrast to the confidence that the overall Exos design exudes.



What about real world performance?

I took this pack on a three day off track walk in the Grampians’ Victoria Range. Yes, I took a brand new lightweight pack off track into the most rugged range in the Grampians. At the walk start, the hardened trip leader looked at the bag, then at me, wagged his head slowly, and assured: “It’ll get shredded”. My walking colleagues then shook their heads, silently in unison.

Unperturbed, I loaded the Exos up with 10kg of gear plus 4 kg of water. Though the internal space is somewhat concave, the volume was ample for my gear. Tent poles fitted easily, despite the curvature. My previous lightweight pack used a foam pad as a frame and the improved load carrying performance and comfort of the Exos was immediately evident. It was larger than I expected inside: the 48 litre capacity looks to have sufficient volume for winter trips which require bulkier equipment.

The suspended trampoline pad ensures there are no digs in the back from poorly placed items. The stretchy side pockets allow bottles to be extracted on the move without taking the bag off, putting them back is trickier.

Once we left the access track and headed bush on a bearing, to preserve the pack, I relocated my water bottles from the side pockets to inside the pack. I eventually stowed the removable top inside to obtain a sleeker profile and reduce the chance of snagging on trees and scrub.

It performed comfortably and faultlessly on the first day. The Exos then compressed down well for the following day trip, thanks to an excellent internal load cinch strap and the zig zag routed side compression straps.

The frame is quite stiff and a couple of narrow rock canyons saw some scuffing on the bottom frame corners. No serious damage: the frame is stiff but does have some give in it. The frame corners are sheathed with a plastic sleeve inside to help protect this area.

Light rain beaded up readily on the packcloth. Seams are not sealed, so sealing or a pack liner would be required for use in wet conditions.

The large rear pocket is great for a wet tent fly or rain jacket, I stowed my scrub gloves there.

On the final day, some brittle dead branches poked a small hole and made a short tear in the soft mesh of the side pockets. I had hoped to return entirely unscathed, but this damage is minor and was comparable to the wear and tear endured by the heavier equipment of my walking colleagues in the rough terrain.

Overall, I was very pleased with the field performance of this pack. The profile of it fitted quite well within my body outline, so my path through the bush was mostly unimpeded. The close fit gives security on exposed rocky scrambles- I never felt like I would fall or be pulled backwards off a rock face by the pack. It is highly functional, easy-to use and will certainly accompany me on many future adventures.

Design, Comfort & Durability (Rating: 90%)

Osprey Exos 48 Backpack Review
Osprey’s pack design experience is clearly evident in a well-resolved design.

The frame and harness provide superb snugness. Load carrying comfort depends on a good fit due to the firm frame. Lightweight packs typically have no harness length adjustment, and all straps are shorter, so fit is important. The rigid frame could cause rubbing problems if the size is not right.

The most delicate area of the pack is the soft perforated stretch mesh used on the external pockets. These stretch mesh inserts are susceptible to damage from snags.

The second factor affecting this bags durability is the pack cloth. The Exos main body is of 100 denier nylon, conventional packs typically use 420 to 600 denier nylon. The nylon is High Tenacity, which assists with the tearing resistance of the lower weight cloth. Wear points on the corners are reinforced with textured heavier 210 denier cloth.

While the stitching is all single row, it is well executed and the seams are all bound.

Functionality & Ease of Use (Rating: 80%)

All straps are suitably dimensioned for a lightweight pack, and trimmed to a reasonable length: you don’t need to cut off and seal extra metres of flappy straps.

Exos has a one handed drawstring opening, which I really liked. (not surprisingly, people seem to have something in one hand when wanting to open the pack) I found this indicative of Ospreys attention to detail, which is clearly informed by field use.

Exos 48 weighs 1150g and can be readily stripped to just under 1000g. It gives excellent load carrying capacity for its weight.

Osprey provide a detailed Owner’s Manual which explains Exos’ features.

What I Like

  • Wonderful weight carrying capacity.
  • Trampoline back panel for comfort and ventilation.
  • Thoughtful, experienced design. Nice details, and faultless build quality.
  • Readily available in retail stores (don’t underestimate this – much bleeding edge lightweight equipment is purchased sight unseen from overseas cottage suppliers).

What I Don’t Like

  • Removable lid with inside and outside zippered pockets is fiddly.
  • External pockets stretch mesh fragility.
  • No hip belt pockets.
  • Multiple external attachment loops which can snag.

Get One

The Osprey Exos 48 Backpack is available online from Wild Earth.

Osprey have provided a backpack for review. The above purchase link is an affiliate link, meaning The Bushwalking Blog receives a small percentage of any sales (but you don’t pay a dollar more). None of this has any effect on the opinions provided in this review.

Have you tried the Osprey Exos 48 Backpack? Got any questions or comments? Let us know by commenting below.