Osprey UNLTD Antigravity 64 Pack Review


Our Osprey UNLTD Antigravity 64 Antigravity Pack Review details a top of the range mid capacity pack with many cutting edge features.  We hope you find the infiormation useful.  


Osprey asked me to review this pack and, as much as I love reviewing Osprey products, I almost refused. Why?  I want the outdoors to be an inclusive place where as many people as possible can enjoy its many benefits.  Having the right equipment to do this safely is important.  Having the right gear can also make it more enjoyable and allow more boundary pushing. 

However,  I certainly don’t want to send out the message that people need to spend huge amounts to access the outdoors.  My early outdoor days were spent in second hand clothes and using products that were as cheap as we could find.  We managed fine and made many great memories along the way.

What does that have to do with this pack?  Well, the Osprey UNLTD Antigravity 64 is a pack retailing for £650.  Wow!  I have never spent that much on a rucksack and doubt most other people have.  It is an eye watering amount and there are plenty of other rucksacks on the market that will do the job this pack does.  Indeed, there are plenty of other options in the Osprey range that will stand their own against this pack.  

But I did agree to review it and my reasoning was simple.  Osprey have aimed to produce a pack which is at the very cutting edge of pack design and, as far as I know,  there is nothing else on the market like it.  They even describe it themselves as an industry changer.  This type of innovation is inevitably going to come at a significant cost.  Cost in the research and development to create the pack and the cost in producing such a complicated product.

Front Entry Zipper & Ice Axe/Pole Attachments

Cutting Edge Design 

No detail has been left unconsidered and no expense spared to produce the UNLTD pack series.  They have produced a beautiful product and many might consider it a worthwhile investment.  But, ultimately, even if you don’t go on to buy one of these, you are still very likely to benefit from it eventually.  

Why? The outdoor clothing and equipment industry is moving apace and the equipment we use now is so advanced that many of the features wouldn’t have even been considered only a few years ago.  But these advancements are driven by companies like Osprey producing items like the UNLTD.  Manufacturers that are willing to put resources into developing technologies that will eventually benefit us all.  So,  there is little doubt that features we see on the UNLTD will soon enough cascade into other products in the Osprey line up.

Osprey UNLTD Antigravity 64 Pack Review

So, please do read my Osprey UNLTD Antigravity 64 Pack Review regardless of whether you plan to buy one or not.  It is a fascinating product and marks the current benchmark for the highest end of pack design.  It also shows what is possible with current technologies and what will eventually be more widely available.  You might also end up deciding you are someone willing to make the investment to have this product in your gear store.  I have tried to keep the review concise and yet there are a lot of features to consider.  Please bear with me on that too!

Lid Pocket


Key Statistics

So, where to start?  The Osprey UNLTD Antigravity 64 Pack was released onto the market in March 2022.  As it’s name suggests, it has a 64 litre capacity and is available in two sizes for men.  The men’s sizes are S/M (81H x 41W x 39D) and L/XL (86H x 41W x 39D).  The capacity of the S/M is 64 litres and the L/XL is 67 litres. 

There is also a women’s version which is available in two sizes. There is XS/S (75H X 41W X 39D) and M/L (80H X 41W X 39D).  The XS/S has a 61 litre capacity and the M/L is 64 litres.  Beyond the general sizing, there is lots of adjustability to tailor a personal fit, but we’ll get on to that in detail later.

Back Panel

The back panel of the Antigravity has been made from 3D printed using polyurethane (PU).  This has been chosen as it offers a soft and comfortable fit with excellent ventilation.  Then, there is a 3D printed Fitscape lumbar pad with Carbon DLS technology.  Manufacturing the lumbar pad in this way allows Osprey to create different densities across the pad to maximise comfort and support where needed. The back length is adjustable either on or off the body by pulling two side mounted straps.

3D Printed PU Backpanel


Like everything on the Antigravity, there are other significant harness innovations.  The pack features what Osprey call a Zero-Lift harness with auto adjusting Load-Lifter technology.  This means that, instead of separate strap tensioners on the shoulders, the auto-lift system creates a loop that lifts and tightens the harness with a single pull.  This combines with well padded and sculpted mesh lined shoulder straps.

The hip belt is very well padded and sculpted.  It is significantly wider than many hip belts I have used and the design aims to distribute the load effectively.  It also features a raised printed PU pattern to reduce wear.  There is a zipped pocket on the left side of the hip belt for smaller item storage. There are also plastic bumpers that protrude from the bottom of the pack on each side.  These should help with stability, but also offer protection when the loaded pack is stood on the ground. 

Elasticated Side Pockets


The pack features an anodised 7075 aluminium frame.  This frame is effectively a wire that runs across the top of the body to offer support while maintaining the shape of the pack.  It also aims to evenly spread the load across the pack and improve flex control.


The Antigravity 64 has a single main storage compartment, although this can also be partitioned off with a compression divider roll at the bottom.  This allows compact storage of bulky items like sleeping bags or jackets.  The main compartment utilises ‘reverse panel loading’ for easy access.  This allows the pack contents to be fully accessed via the large clamshell style zipper.

Alongside that are 2 zipped front pockets and 2 elasticated mesh side pockets.  The mesh side pockets can be accessed either from the top or from the side.  The side entry option is designed to be usable while the pack is being worn.

Detachable Lid


Osprey have used a selection of high performance fabrics.  The main pack body is made from a material called UHMWPE grid.  UHMWPE stands for Ultra High Molecular Weight Polyethylene.  This is a 210 denier material designed to offer both lightweight and durability.  

Other Features

There are lots of other nice details on the Antigravity 64.  These include dual injected zip pulls and strong and break resistant TPOM YKK buckles.  The zip flaps are laminated and the zips are water resistant.  There are also tuck away ice axe loops and variable woven ski loops.

The Antigravity 64 has hydration system compatibility (although a bladder isn’t supplied with the pack) and there is external access to the reservoir.  The drink tube is routed through injection moulded hose routers. 

The pack weighs 2.5 kgs.  It also comes with a high tenacity ripstop nylon deluxe rain cover that can be stored in a zipped base pocket.  Osprey also provide a high tenacity ripstop nylon AirPorter transit cover with the pack.  The cover is designed for protection during travel or storage. 

Additional Storage Front Pockets

In Use

The first thing you will always notice about any pack is the appearance.  The UNLTD Antigravity 64 men’s comes in a blue colour and the women’s in a green/teal colour.  On both models this is contrasted by black back and strap features.  The packs look great.  I also really like the shape. The pack is a fairly squat cuboid shape that looks streamlined and stable.  I hoped that this impression was backed up when I loaded it up and carried it.  Overall, I would say the pack looks subtle and stylish.  

Loading & Unloading

The next thing you will want to do is load the pack.  To load the main compartment you have two options.  If you unzip the clamshell main zip you have access to all the interior.  This gives great access, but you will usually want to lay it on its back panel to use it this way.  For this reason it works best if you are laying it on a clean surface.  This is a great option for easy access inside a tent or Alpine hut.

The alternative for accessing the main compartment is the horizontal water resistant zipper at the top. This allows quick access to contents at the top.  Providing you have planned what you need during your day, this is a quick and easy option. 

Inside the base of the main compartment there is a clever compression roll.  This is designed to store and compress bulky items like sleeping bags or insulated jackets.  It is a useful addition although worth mentioning that it doesn’t offer any weatherproofing to the contents. It would have been interesting if Osprey could have incorporated a dry bag style system here.

Raincover Pocket

Other Storage

Alongside the main compartment there are two externally accessed zipped side pockets.  One covers one side of the pack and one the other.  They are very easy to access and they make access to on the go items very simple. You could use these for anything from waterproof layers to food and drink.  They are a great addition.  

On the lower wings of each side of Osprey have added a stretchy storage pocket.  They feature reinforced bases and the right hand pocket has a side opening for on the go access.  Again, I consider these another great addition.  The left hand one will securely hold clothes, drinks bottles, food or any other quickly needed extra.  The right hand one is ideal for on the go hydration or quick access to clothing such as hats and gloves.  You can also store longer items like tents poles in the pockets (this particularly suits the left hand one) as the items can then be easily secured with the side compression straps.

A final zipped pocket on the left hand side of the hip belt makes the ideal home for on the go essentials such as a compass, snacks or sunglasses.  

Zero Lift Harness

Hydration Compatible

There is one other access zip at the top of the mesh back panel.  This gains access to the hydration pocket.  There is a hook to hang your bladder from and the tube can then be routed on either side of the shoulder straps via through some injection moulded clips.      

All the zips have injection moulded pull tabs making them extremely easy to operate with gloves on.  With the exception of the one on the hydration pocket, all the zips are water resistant.  When further weather proofing is needed the zips are protected by weatherproof flaps.

Carrying Comfort

All the attention to storage detail means nothing if the pack isn’t comfortable to carry.  So this Osprey UNLTD Antigravity 64 Pack Review needs to consider how well Osprey have achieved comfort and stability. 

For once, you don’t actually need to sort pack sizing before putting the Antigravity on.  All you actually need to do is pop it on your back and pull the side adjuster straps to get the optimum fit.  This slides sleeves along the frame poles and really couldn’t be simpler, quicker or more effective. It works superbly.  Once that is adjusted, you can pull two other straps to securely pull the pack into your shoulders.  Again, it works effortlessly and extremely quickly.  Once all that is sorted out you can adjust the hip belt and fasten up the sternum strap.

The hip belt is extremely supportive and comfortable.  The Carbon DLS Lumbar Pad, curved hip hugging side wings and dented padded hip belt design locks it comfortably and, providing the right back length is achieved,  offers excellent load transfer onto the hips.  As you would expect, the shoulder straps are well sculpted and padded.  The sternum strap includes a whistle.

So, the Antigravity offers excellent load carrying comfort.  It also offers superb stability. I’m sure this is a lot to do with the harness, but undoubtedly the frame also really assists with this too.  The  wire frame curves around the top of the pack and adds rigidity without affecting freedom of movement.


Lid Pocket Converts To Waist Pack

Waist Belt/Lid

The Antigravity has a further trick up its sleeve.  The pack comes with a lid that doubles as a waist pack.  And when I say waist pack, I mean a very comfortable and functional waist pack.  The pack has a padded back and waist belt, a large main pocket and a smaller front pocket with interior key clip.  

This offers great flexibility.  Leaving the waist pack at home simplifies the pack and saves weight.  Taking the waist pack offers additional storage and convenience.  It also means, if you are making trips from a basecamp, you could leave the main pack behind and take the waist pack with essentials.  Alternatively, you can wear the waist pack at your front while wearing the main pack. This is ideal for travelling where you might want to consider security in some situations.  It also means that users like photographers could keep quick access to cameras.  It is a versatile addition. 

Other Features

You can carry single or twin ice axes.  You can carry skis either on one side or a ski on either side.  The side compression straps make volume adjustment simple while allowing additional items to be attached.  A removable rain cover is stored in an underside zipped pocket.  Two extra straps at the bottom of the front section could hold items like a sleeping pad.  No stone is unturned in offering versatility for many users and situations.   

3D Printed Fitscape Lumbar Pad


Without Compromise

Our Osprey UNLTD Antigravity 64 Antigravity Rucksack review reveals a pack designed and manufactured without compromise.  No stone has been left unturned to create a state of the art pack offering exceptional comfort and performance.  Of course, whether it suits your needs and budget is a decision for the user.  It is very expensive and, for some, will potentially have too many features and be too heavy.  For others the benefits will make the weight and investment worthwhile. They will also be happy that the pack weight is offset by comfort and functionality.    

Either way, one of our main considerations in reviewing this product was about what this type of product offers for future pack development.  By that criteria there are many features on this pack that are definite leaps forward.  The Zero-Lift harness, for just one example, is superb.  I’ve never used a pack that allows such quick, simple and efficient on the move adjustment.  

A Pack For Many Adventures

The pack is extremely stable and moves with you, even when substantially loaded.  This makes it comfortable for carrying over longer distances and on tricky ground.  It also features all the extras you need for just about any adventure.  From carrying skis to loading it up for a multi-day journey, the Antigravity 64 has you covered.  This is also helped by innovations like the removable lid.  This type of extra adds great flexibility.  You can carry the pack into a base camp and then use the lid for your summit push or strip it off the pack and leave it at home.  Any variant is possible.  

Cutting Edge Innovation

Overall, I really applaud Osprey for producing an extremely innovative and highly functional pack.  The rucksack delivers as promised and the innovations will be sure to end up in other packs down the line.  Full details on the Osprey UNKTD Antigravity 64 Pack are available via their website here. Please also watch the video below which explains the UNLTD series in more detail. 

We have been proud to work with osprey over many years and this Osprey UNLTD Antigravity 64 Antigravity Pack Review is only one of many products we have reviewed.  All the recent reviews are available on the review section of our blog here.  Of interest might be our advanced snow sports focussed Soeldon Pro Avy 32 review here or our load hauling Transporter 120 Duffel Bag review here.  We also reviewed the climbing focused Zealot 45 here and the expedition Nimsdai Mutant 90 here.