Osprey Aether Pro 70 Rucksack Review

I’ve watched with fascination and admiration this year as Osprey athlete Nirmal ‘Nims’ Purja has quested his way to a stunning new record on the world’s highest mountains.  Just incase you missed the news, Nims has recently finished his ground breaking challenge and, by climbing the 14 8000 metre peaks in only 7 months, has completely smashed the previous 7 year record.  Incredible.

I was also intrigued to see that Nims had used an Osprey Aether 70 Pro pack for his ascents.  A 70 litre pack seemed quite big, but I knew Nims often ended up carrying quite a lot of his own equipment.  I also knew of the Aether to be a very lightweight pack and so wondered how well it might stand up to the rigours of expedition life.  Well, it obviously had survived for the many ups and downs of Nim’s challenge.  All in all, I thought this was a pack I needed to find out more about and Osprey kindly sent me one to test.  Here is my review…..


Where to start?  The Aether is jam packed with features.  I’ll start with the materials and work from there.  The Aether is actually made from 4 types of fabric.  The main body is a combination of 210 denier Nano Fly and 200 denier UHMWPE Nylon X. That already sounds complicated, but as is usual with Osprey, everything is done with good reason.  UHMWPE stands for Ultra High Molecular Weight Polyethylene. This is the base fabric often branded as Spectra or Dyneema and it’s big advantage here is that it offers great strength and durability for extremely light weight.  In reality, this means the fabric in 200 denier equates to a 400 denier standard material in abrasion resistance. Very impressive.

The other fabrics used in the Aether are a 315 denier nylon Oxford as an accent fabric and a durable base constructed from 200 denier UHMWPE.  The upshot of this is that Osprey have chosen some of the most durable fabrics at very light weights – certainly not the cheapest, but very high performance.

Next, let’s consider the all important harness.  Any load hauler needs a harness that will provide stability, comfort and durability – it is a big ask for manufacturers to get this right in bigger packs. For the Aether, Osprey have created both stability and support by using a 7075 tubular aluminium peripheral frame combined with a single 6061- T6 central alloy stay. They call this their Lightwire Suspension.  7075 aluminium is extremely stiff and durable (you might be familiar with it as a common material choice for tent poles) and 6061 is another strong, durable and stiff choice. If you imagine the forces placed through this structure it certainly needs to be able to stand up to considerable forces.

This is combined with an Airscape aerated mesh covered foam back panel.  The foam panel incorporates ridges to aid ventilation.  The shoulder straps feature Isoform 4 with a mesh spacer harness and the waistbelt is a heat mouldable Isoform 4 CM model. There is a sternum strap with incorporated whistle and, although the pack comes in 3 sizes, each size is also adjustable for an individually tuned fit.

Storage is based primarily around the single main compartment and this incorporates a hydration pocket to house up to a 3 litre Osprey Hydraulics bladder (other makes of bladder will work too).  Then there is a floating lid pocket sized to hold daily trail essentials (this lid is removable – but more detail on this later) and there are also 2 removable side pockets positioned on the fins of the hip belt. One of the hip pockets has a zip closure and one is closed by a cinch able cord system.  

Osprey have added an external compression/gear attachment system combining 2 straps that sit across the front of the pack and there’s a single z strap compression strap down each side.  This combination gives loads of flexibility to attach trekking poles, tent poles or even skis (although you’d want to protect the fabric from ski edges). The compression straps can be removed to save weight if required.  

After that, there are twin ice axe attachment points, a quick store trekking pole attachment system that can be used even when the pack is on, removable sleeping pad straps and reinforced external attachment points that allow additional equipment, or even a small rucksack, to be attached outside.  

In Use

I’ve tried to keep the features section as brief as possible, but it is evident there is a lot of detail to discuss with the Aether 70 Pro.  I’ll try and be succinct with this section too, but bear with me as I think this will take a fair bit of wordage to discuss in sufficient detail.

So,  first things first. You need your rucksack to perform well but also want it to look good.  Fair to say that, in my humble opinion at least, many ultralight packs don’t look that great.  They might perform well and be extremely efficient, but they can be rather the ugly ducklings of the pack world.  I have to say that I think the Aether Pro 70 rather bucks that trend.  It might not be in the same visuals league as a stylish streamlined climbing pack, but Osprey have done a great job with the appearance.  The rip stop appearance of the white/grey fabric looks great and splashes of colour like the red compression straps and contrasting accent pieces add a bit of design flair. The appearance is also helped by the long single streamlined main compartment.  The Aether looks sleek and yet designed to perform.

Which inevitably brings us on to performance.  Osprey have designed the Aether for long backpacking trips but also for expedition mountaineering.  To tick the boxes for these contrasting user group it needs to have the features to manage very different environments and the durability for both – durability in this case being especially important for the mountaineer who will use the pack in hostile situations.  

The Aether is already very light at 1.89kgs (this is already around 1kg lighter than many packs in this class), but Osprey have also cleverly made it extremely customisable.  Remove the 2 hip belt side pockets, for example, and you’ll save about 160 grams.  The floating lid can be removed to save about 150 grams and side compression straps another 50.  Infact, strip all the strippables and you can save almost 400 grams on the Aether’s total weight.  Suddenly, at about 1.5kgs, the pack is extremely light for something of this size and functionality.

Of course, it also needs to be considered that every storage item you remove also reduces the capacity.  I estimate that stripping everything back will reduce volume by about 10 litres.  But, there are times you don’t want the extra height of a lid pocket or the side width of the hip belt pockets.  It is great to have that customisability for different situations.  

Then there is the fit and load carrying capability. It is clear that a lot of thought and testing has gone into the harness and back panel design and the Osprey team have done a great job.  The fit can be fine tuned to back length because, as well as the 3 size options, the easily adjustable back panel allows plenty of fine adjustment.  The shoulder straps and well padded back panel give great support and then there is the hip belt.  

Osprey’s heat mouldable Isoform hip belt system offers great support and it is very comfortable.  I’m sure anyone looking at such a pack will be well aware of the need to shift load onto the hips, and this does that with ease.  The hip belt is also very easily tuneable by using the twin strap adjustments to get a centralised fit.  It is great.  I have to say that I haven’t considered heat moulding the system yet as I haven’t felt the need, but I’m sure, just like forming the shape of your ski boot inners, this will fine tune for a very personalised fit.  

In terms of load carrying, I previously mentioned that the Aether features a large and yet streamlined single main compartment.  This is my preferred system and it swallows gear effortlessly.  Systems like this need thought so that you have the right things where you need them and my preferred method is to use ultralight dry bags for key items.  If you haven’t then maxed out on capacity there is the option for using those compression straps.  Inside the main compartment is the bladder sleeve for up to a 3 litre bladder size and this integrated effortlessly into the whole system.

The floating lid is a good size for all those trail nik naks you might need, but I have to say that more often than not I’ve actually left it off.  This saves a little weight, gives the pack a more streamlined shape and I often don’t feel the need for all that top storage. Long tall packs of this type can sit very high on the back and so removing the lid pocket helps reduce this height and I like doing this when practical.  On some packs leaving the lid off would be a natural entry point for rain or snow but, on this as on many Osprey packs, they have included their genius FlapJacket lid cover.  This is essentially a small and functional mini lid that covers the main opening and yet sits flat against the main body of the pack.  I’ve used this a lot on other Osprey’s and think it is fantastic.  At the end of the day it is great to have a choice.

The other storage comes in the form of the removable side pockets.  These fit alongside the fins of the hip belt and are designed to allow storage of small items and easy access to the pockets while the pack is being worn.  They are streamlined and work really well.  One is zipped and is a great place for small items like lipsalve, a compass, sunscreen, sunglasses or similar.  The other closes with a cord system and is best suited to things like a Nalgene drink bottle, hat or Buff – things that won’t find their way easily out of a small opening. I’ve also used this side pocket for maps.

In use you can access these pockets and they do their job of storing small items.  They are also easily removed when not needed.  I have found that they can be accessed successfully with the pack on and unzipping the zipped side with one hand isn’t an issue at all.  They feel an integral part of the pack. The only consideration is that they don’t have the volume of some hip pockets, but what you lose in storage capacity you gain in their streamlined shape. 

Other storage features work as they should.  You can attach ice axes, the trekking pole attachment system is a great idea if you will be tackling mixed terrain where you need to sometimes be using your poles and at others have your hands free. I haven’t used the sleeping pad attachment in anger but can see it will work fine – I tend to carry one of the new generation of superlight inflatable mats nowadays.  Similarly, the external attachment points that allow a small rucksack to be attached are a good idea for some, but in a pack of this size I imagine that won’t be used too often – it was something I did when travelling some years ago and it is the sort of facility you might use if, for example, you were carrying supplies into a remote base camp.  So, it will have its uses for some.  

As expected, the combination of superb Osprey build quality and ultra durable materials are standing up well to use.  I fully expect users will get many years of solid use out of one of these packs.  This is as well, of course, given that they come with a hefty £300 price tag.  But, I actually think, when the technology, high spec materials and R&D time that goes into a product like this, this represents good value.  These types of products are specialist items and there are cheaper items on the market that will do similar things, but if you can stand the cost I would pick the Aether Pro any day.  It is a great product at the frontier of pack technology. 

Finally, a mention that Osprey produce a female fit version of this pack called the Ariel Pro 65 and, although I imagine many of my observations of the Aether will hold true for that pack too, I haven’t any personal experience of it.


The Aether Pro 70 is at the cutting edge of large load hauling packs that will work in a range of terrain types.  It utilises excellent build quality, state of the art materials and very intelligent design to produce a customisable pack for many user types and very different environments.  It isn’t cheap, but then you are getting a lot of pack for your money.  I think this is a fantastic addition to the Osprey range and they should be applauded for producing packs that, while not having a huge user base, do show what is currently possible.  Let’s be honest, buying an Aether Pro isn’t going to make any of us smash out multiple records on the worlds highest mountains like Nims, but it is good to know what has been achieved in this pack when you need to trust it for your own challenges. Another great option from the pack specialists. Full details are available on the Osprey website here

Posted by Paul