Get ready for your next adventure

It took us 12,000 miles of hiking to design our perfect backpack: The Mo – a lightweight, fully-featured load hauler, purpose built to support you on your next adventure.

We designed The Mo to suit the average thru hiker using modern, lightweight gear, with a base weight of up to 10kg/22lbs. We use lightweight, durable materials that are easily able to cope with heavier loads and heavier use. If you are heading out onto rough and overgrown trails like the CDT or Te Araroa, then the Mo is for you!

With a load capacity of 19kg/42lbs and pack weights starting at just 890g/32oz, The Mo won't weigh you down.

Weight From 890g / 31.4oz (40L, size M)

Load capacity 19kg / 42lb


Packing Space

Main Pack body
The main body of the pack is completely open, yours to fill as you wish. It is secured with a roll top closure that can be secured vertically for added compression or dry bag style.

Large front pocket
The front pocket can be sewn in either Dyneema Stretch material or Bullet Net, both offer capacious storage. The Dyneema Stretch is better for a cleaner aesthetic and off trail bushwacks (doesn't snag easily) and the Bullet net is better for packing wet gear and improved visibility of items but can snag when bushwacking. The bullet net option will increase the measurable volume of your bag by 5L.

Side pockets
Each pocket can hold 2.5L and are perfectly shaped to carry 2 x 1L smart water style bottles with ease. You can use the elastic drawcord to secure these items whilst walking and, should the elastic ever break or wear out, we have designed it to be easily replaceable.

Load Carrying

S-shaped shoulder straps
Sewn using 10mm foam, durable 210d Robic Extreema face fabric and breathable, soft 3mm spacer mesh

Padded back panel
Uses shaped 8mm closed cell foam. Can be removed when the pack is empty for a 25g weight reduction.

Removable contoured hipbelt 
Comes with 4 adjusters that tighten by pulling inwards allowing you to dial in the perfect fit. Can be removed.

Lumbar pad
Made with 10mm EVA foam and 3mm thick spacer mesh. 

Sternum strap
Elasticated and height adjustable.

Plastic Frame with removable Alloy stay
Removable frame sheet made of 1mm thick plastic with a sewn-in 12mm / 0.5" alloy bar. The plastic for a medium frame weighs 91g / 3oz, with the alloy weighing 58g / 2oz.

Add More

Shoulder pockets (optional)
Super stretchy and big enough to hold most smartphones, a day’s worth of snacks or a 700ml water bottle. The elastic is fixed and, owing to its clever design, does not need a tensioner.

Front zig-zag elastic (optional)
Removable and designed to be able to store a folded Z-rest or assist with air drying your clothes.

Side elastic with Lineloc (optional)
These are there to secure a trekking pole or tent poles when stored in the side pocket..

Ice Axe loop (optional)
Sewn-in loop to easily connect an ice axe or walking poles.



  • Weight* 890g / 31.4oz
  • Load capacity 19kg / 42lb
  • Height fully unrolled 74cm / 29"
  • Circumference at base 81.3cm / 32"
  • Circumference at top 91cm / 36"
  • Main body volume 35L
  • Side pockets volume 2 x 2.5L

* Based on Medium Torso Size before additional customisations


  • Weight* 910g / 32.1oz
  • Load capacity 19kg / 42lbs
  • Height fully unrolled 82.5cm / 32.5"
  • Circumference at base 86cm / 34"
  • Circumference at top 94cm / 37"
  • Main body volume 45L
  • Side pockets volume 2 x 2.5L

* Based on Medium Torso Size before additional customisations


  • Weight* 965g / 33.8oz
  • Load capacity 19kg / 42lbs
  • Height fully unrolled 91cm / 35"
  • Circumference at base 89cm / 35"
  • Circumference at top 99cm / 39"
  • Main body volume 55L
  • Side pockets volume 2 x 2.5L

* Based on Medium Torso Size before additional customisations

Good to know

Can it fit a Bear Can?

BV450 will fit with the base to your back or a BV500 will fit vertically with a little room at the side for a stuffsack.  

How long will it take to make?

Making great things takes time! Our lead time lets you know our estimated production time frame, this may change depending on demand, time of year and staff availability.

Up-to-date lead time can be found at the top of every page on our website.

Once you have placed an order, we update you every few weeks to let you know how things are progressing.

How much does shipping cost?

Shipping rates are calculated at checkout based on your delivery information.


£3.95 Small Parcel (every small parcel ships on a 2 week lead time)
£7.95 for orders over £140 


£10 5-10 Days
£25 for orders over £120


£10 5-10 Days
£25 for orders over £120

The rest of the world

£15 10+ Days
£35 for orders over £120

If you live in a remote location, we may occasionally need to charge a small extra surplus for shipping. This will be calculated when we ship the pack.

Customers outside the UK will not be charged the 20% VAT included in almost all of our prices, but you may be subject to local tax and import duties.

Full details on our shipping page.

Can I check out in another currency?

Yes! Scroll right down to the bottom of the website and on the left you can select your home currency - this will automatically show you the correct VAT free price for overseas delivery.

A quick video run-through of the Mo

The Mo

Your Lightweight Load Hauler

Fully featured

The Mo is packed with features that let you carry everything you'll need. Stretchable pockets, handy loops and fastenings that can all be used to maximise your load, without sacrificing weight.

Designed for distance

Created in our Cumbrian workshop for the needs of the most seasoned thru-hiker, The Mo cleverly utilises the latest materials to give you the freedom to carry the kit you need, the way you want.

The Mo

Lightweight design. No compromise.

It took us 12,000 miles of hiking to design our perfect backpack: the Mo – a lightweight, fully featured load hauler, purpose built to support you on your next adventure.

How to choose

The Atom+ vs The Mo

Which is right for you?


Customer Reviews

Based on 26 reviews
Fantastic backpack!

I own the Mo (40L) for a few months now. Have used it for travelling as well as a trail (4 days). Love the quality and the features of the Mo. The backpack is very light and versatile, fits well to my back also during difficult passages during a hike, including some climbing sections.
The rolltop works well and the backpack was able to fit my gear and food for 4 days (tent was carried by another member of our group though).
The only feature I have been missing is a small, zipped pouch somewhere (for example a the inside of the rolltop or attached to the inside frame pouch) where stuff like a wallet/passport and/or keys can be stored when travelling. Helped myself with an additional small pouch attached to the very practical hook inside the top of the backpack.

Overall, the backpack absolutely lives up to the very high expectations (after so many great reviews).

The whole ordering process was also very smooth, transparent and really friendly. Thanks you so much to the team at Atompacks!

Still going strong

I had a custom Mo made by Atom Packs a few years ago when the company was moving locations. I don't backpack a lot, but the bag is still going strong. There are an absolute ton of tiny features that make this bag so nice. Extremely appreciated. I can carry a week-long kit in the 40L, and it's nice and comfortable against my back. I don't think I'll ever need another backpack. Very happy to see the company is still going.

Cape Wrath Trial

I recently completed the Cape Wrath Trail with my Mo50 pack. This is definitely one of the best packs I have ever owned. I am 54 yrs old, 5’11”, 82kg. I would describe my packing as ‘Comfy-Light’; my base weight was just over 14lbs. My maximum carry was 4 ½ days food. 6 days food would have been pushing it with the roll top; I would have needed the 60L version. The load transfer is excellent. The pack / shoulder straps fit me so well, I mostly did not use the sternum strap. This allowed me to vary the pack position from maximum venting, to keeping me warmer depending how close I had it to my back. I have had another ultralight hiking pack and it wore out quickly. On that pack the elastic went on the pockets, the fabric was flimsy and a zip failed. The fabric on the Mo is much more durable and I really like the fact that all the pockets are secured with replaceable bungee cord. The pack makes a great winter day hike pack so it is very versatile.


Just like to say how pleased I am with the new mo EP50 which I received this morning, so light and beautifully made can’t wait try it out.
Thanks atom team..

So comfortable

I love this bag so much. It survived being dragged off by a raccoon in the night! It is super comfortable to wear and easy to adjust to fit. Having the large net front pocked allowed me to stuff a wet tent in there and keep the rest of my gear dry inside the pack and liner. One shoulder strap and one hip pouch were perfect for my phone and daily snacks. Also love the pocket on the bottom for poking snack wrappers in throughout the day. Thank you Atom!