BUILT TO SEND X0 Rucksack Review

BUILT TO SEND is a British rucksack manufacturer focussed on producing the highest performance packs for climbers and mountaineers. They asked me to review an item from their range I instantly knew their BUILT TO SEND X0 rucksack would be perfect. The X0 is, as they describe, their ‘ultra-minimal model designed for fast and light missions in Alpine terrain’.

I occasionally need larger capacity rucksacks, but for 95% of my adventures something around 30 litres capacity is bang on.  Built to Send kindly sent one across and I received it towards the end of the winter.  I had time to use it for several days in Scotland and then took it for a mountaineering trip to the Atlas Mountains.  

During that very trip, which I recounted in my blog post here, the world turned upside down! Seemingly overnight we all faced the new adventure of a countrywide lockdown and a global pandemic.  This curtailed my ability to review the BUILT TO SEND X0 rucksack a little but, given my time leading up to the lockdown and my busy period of activity following the easing period, I feel very confident I can thoroughly review the pack.  So, here is my BUILT TO SEND XO rucksack review.


My long held preference is for climbing packs to be, essentially, a bag with straps.  Of course that is massively underplaying the technology manufacturers incorporate into their products, but I simply mean that keeping it simple in terms of features and unnecessary ‘bells and whistles’ really pays dividends for mountain packs.

So, from first inspection I was an immediate fan of the X0.  Apart from a small zipped internal pocket, the large main compartment is all you get.  This closes with a roll top design and then there’s the shoulder straps and a waist belt.  Keeping it simple.

But behind that simplicity is a lot of hidden depths.  BUILT TO SEND focus on indestructible construction and this is evident everywhere you look.  The main body is made from a single piece of expedition grade composite VX42 X-Pac fabric.  This ensures an almost seamless design. BUILT TO SEND claim the only way to break one of their packs means tearing through one of the toughest materials on the planet. The fabric is also 100% waterproof. This means, although the seams aren’t taped, it will offer very good levels of water proofing.

When designing the contoured shoulder straps BUILT TO SEND weren’t happy with the padding material options available and so developed their own.  This is a 10mm thick physically cross-linked polyethylene foam (based, they say, on a type used in fighter pilot seats). The properties of this foam give it excellent load spreading capabilities. Perfect for shoulder straps. It also makes the back panel forgiving of poor packing when fully loaded. The shoulder pads are shaped to be low profile for harness compatibility. 

The BUILT TO SEND X0 rucksack features a simple unpadded 50mm webbing waist belt. This isn’t removable but it can be looped around the back of the and secured. In this way it doesn’t get in the way for climbing activities.  The waistbelt closes with a plastic quick release buckle.  The final part of the harness system is a quick release buckled sternum strap.        

All the other hardware on BUILT TO SEND packs is custom-designed and engineered from aerospace-grade aluminium.  These buckles are quite a work of art too – they all feature the company name and are hard anodised.  

The front of the pack features a daisy chain system for attachment of accessories. There is also a line of buckles to allow almost infinite adjustment of the compression straps.  Finally, a hand loop and haul loop system finishes the weaponry. The pack closes with a roll top system that fastens with more of those sleek alloy buckles.  

The packs are stitched with seam allowances almost twice the industry standard. Structural seams are triple stitched using V92 bonded polyester thread. This is a level exceeding the military specification for safety-critical equipment.  Any load rated webbing is bar-tacked for strength.

One last point.  BUILT TO SEND hand build their packs in limited numbers in Great Britain under an ISO 9001 quality system.

In Use

As mentioned, the BUILT TO SEND X0 is about 30 litres in capacity.  I say this because it is actually variable between 25 and 35.  When closed fully it is about 25, but the roll top allows expansion to the ‘overload’ capacity of 35.  This makes it perfect when you are walking into a route with a fully loaded pack but then, once harness, helmet, rack etc are removed, you want it cinched down so it is low profile enough for the climb. It is the perfect Alpinist system.  

The addition of compression straps and exterior bungee cords (more on this later) along within a wide choice of attachment points also means that any extras can be strapped onto the outside for the walk in. The long straps that loop over the lid also allow the option for rope carrying and they lock down with glove friendly G hook buckles.

There is no frame in the X0, but that is as I believe a smaller capacity Alpine pack should be.  The 10mm insulation/back padding makes it stiff enough to keep its shape and yet I’ve never had a problem with anything poking into my back due to poor packing.  The flat nylon covered back panel also sheds snow well, although it does get sweaty in hot weather. 

Have a feel of the pack’s fabric and you know this stuff will stand up to the extreme rough and tumble of Alpine life.  I can’t claim this is a long term review, but it shows every sign that you’ll be passing this pack onto to your children. There are no signs of wear on the pack fabric at all. Infact, it feels like the sort of stuff you’d want to make a bulletproof vest from!  Even then, BUILT TO SEND have even doubled up the material on the base.  You can really throw whatever you want at the X0.      

I was sent a black BUILT TO SEND X0 rucksack although a white version is also available.  The black pack has a white lining which makes it easier to see inside to fish out that essential item that has inevitably worked its way to the bottom.

As mentioned earlier, the storage compartments only comprise a single main compartment and a zipped interior pocket that is ideal for small items like keys, snack bars or suncream.  No other options, but what other options do you need?!

On the outside BUILT TO SEND have incorporated a well dialled and virtually indestructible haul system and grab handle.  There are load rated haul loops that allow the pack to hang bucket style at hanging belay stances.  This allows easy management of the contents as well as giving the option to use the pack as a rope bucket.  It would also allow you to haul the pack with complete confidence. 

The load carrying harness is minimalist but efficient.  The shoulder pads are really well padded and the contoured shape makes them comfortable enough for long days.  As discussed earlier, BUILT TO SEND specifically sourced the padding material for this. They weren’t happy with other options on the market and so sourced their own.  Great attention to detail and detail that is appreciated when the pack is fully loaded.

The waistbelt is simple and efficient and does what a waistbelt should do on a  pack of this size – adds stability and some level of support.  To be honest I don’t use them often on packs of this type. It is mostly tucked around the front of the pack and secured to the front daisy chain. It is there if you want it though.  The buckle is a side release plastic type which BUILT TO SEND specced so it would be quick to undo in an emergency. The same goes for the sternum strap. 

Each X0 is shipped with an ‘Alpine Customisation Pack’.  This includes four 20mm webbing compression straps with aluminium G-hooks and a shock cord pack for you to create a crampon attachment system and four ice axe retainers.  BUILT TO SEND include full fitting instructions and, given the wealth of attachment points on the pack, you can customise each element as you need.  The straps are long enough to hold a sleeping mat and yet strong enough to attach skis.  The shock cord system also works as you’d want and there is a tape sleeve on the pad to keep ice axe blades securely tucked out of harms way.  The crampon attachment system can also be used to attach anything else.  It is a simple and flexible system that can also be added or removed as your needs change.

The X0 weighs about 850 grams and the Alpine Customisation Pack adds about another 100 depending on the configuration used. For a pack of this build and strength that is a very respectable weight.


I’ve really made no secret of my love for the BUILT TO SEND X0 rucksack.  I prefer packs that are simple in features and yet well thought out in terms of having all the things you just need to work working well.  The X0 ticks every box with ease. These packs aren’t cheap (the X0 retails for £280), but you get a lot of quality for that money and a pack that will be a faithful companion on endless adventures.  

You can tell that every detail has been agonised over by enthusiasts that know from experience what works and yet no expense has been spared in the construction and design. BUILT TO SEND make the bold claim that ‘your pack has been built without any compromise on quality. It’s the finest engineered and strongest pack on planet earth’.  It’s a big claim to live up to, but I think they have every right to make it.  

BUILT TO SEND packs are available through their website here and this small British manufacturer deserves every success.