The Prospector EP50 (Black)

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


£275.00
If any sizes are unavailable, our next restock will be on July 15, 2025

29 reviews
Torso Size
Hipbelt Size Guide
Typically ships within 2 weeks

Perfect additions to The Prospector

The Hipbelt Pocket

The Hipbelt Pocket

£22.50

Sticker Pack

Sticker Pack

£4.00

The Prospector

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

We designed The Prospector 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 then the Prospector is for you!

With a load capacity of 19kg/42lbs and pack weights starting at just 910g/32oz for a size Medium, The Prospector won't weigh you down. 

Specifications

Load capacity
19kg / 42lbs

Weight
910g / 32.1oz (size Medium)

Height fully unrolled
82.5cm / 32.5"

Circumference at base
87.5cm / 34.5"

Circumference at top
94cm / 37"

Main body volume
45L

Side pockets volume
2 x 2.5L

The front pocket can stretch to hold up to an additional 5L in volume.

Features Overview
  • Removable 4-inch Padded Hipbelt
  • Lumbar Pad
  • Removable Large Plastic Frame with Alloy Stay
  • S-Shaped Shoulder Straps
  • Hydration Tube Port
  • Bottom Pocket
  • Dyneema Stretch Front Pocket
  • Removable Padded Back Panel
  • Adjustable Side Pocket
  • EPX400 Base
  • Haul Loop
  • Whistle Sternum Strap
  • Front Zig-Zag Elastic
  • Roll Top Closure
  • Y-Strap
  • Fixed Ice Axe Loop
  • Vertical Side Compression
  • Load Lifters
  • Z Side Compression
  • Sewn In shoulder Pocket

Explore Full Features

Key features

Load Lifters

These use daisy chain webbing coming off the shoulder strap to stabilise and adjust the balance of your pack while hiking.

Key features

Adjustable Side Pocket

Our Forward-facing, deep and low side pocket design keeps your bottles secure while still being low enough to reach into whilst the pack is worn. Each pocket can keep 2 x 1L Smartwater style bottles secure, just tighten the elastic using the pull adjuster.

Each pocket features two drain holes to stop rain collecting in them.

Key features

Y-Strap

The Y strap offers increased support for larger items like a bear can or sleeping pad when stored on top of the pack

Key features

Dyneema Stretch Front Pocket

Made with Dyneema stretch fabric. Can hold 5L, not included in the total volume.

Key features

Bottom Pocket

Easy-access bottom pocket featuring a large opening on the wearer's right and trash port on the wearers left.

Sewn using Dyneema stretch fabric.

Key features

Load Lifters

These use daisy chain webbing coming off the shoulder strap to stabilise and adjust the balance of your pack while hiking.

Adjustable Side Pocket

Our Forward-facing, deep and low side pocket design keeps your bottles secure while still being low enough to reach into whilst the pack is worn. Each pocket can keep 2 x 1L Smartwater style bottles secure, just tighten the elastic using the pull adjuster.

Each pocket features two drain holes to stop rain collecting in them.

Y-Strap

The Y strap offers increased support for larger items like a bear can or sleeping pad when stored on top of the pack

Dyneema Stretch Front Pocket

Made with Dyneema stretch fabric. Can hold 5L, not included in the total volume.

Bottom Pocket

Easy-access bottom pocket featuring a large opening on the wearer's right and trash port on the wearers left.

Sewn using Dyneema stretch fabric.

The Prospector Overview

A quick run through of the features of the Prospector

The Prospector

Needs met.

The Prospector. The Backpack formally known as The Mo

All our bags are designed and tested to meet a specific need. Each item is built by hand to our incredibly high standards right here in our Keswick workshop.

Features

Removable 4-inch Padded Hipbelt

Our removable shaped hip belt contours to the shape of your body for great load transfer. Featuring 4 inch (10cm) wide wings, the fit is adjusted by pulling the webbing inwards for the perfect fit.

Sewn using 11mm foam, durable 210d Robic Extreema face fabric and breathable and soft 3mm thick spacer mesh.

This hip belt is removable and interchangeable, replacements can be purchased at any time from our website.

Lumbar Pad

Helps to transfer load through to your hips. Made with 7mm EVA foam and 3mm thick spacer mesh.

Removable Large Plastic Frame with Alloy Stay

Removable frame sheet made of 1mm thick plastic with a sewn-in 12mm / ½" alloy bar. The frame for a Medium torso length weighs 150g

S-Shaped Shoulder Straps

Our S-shaped straps are designed to perfectly hug the contours of your body.

Sewn using 11mm foam, durable 210d Robic Extreema face fabric and breathable and soft 3mm thick spacer mesh.

Hydration Tube Port

There is an access port for a bladder tube behind each shoulder strap, allowing access inside the bag where there is a hanging clip for your bladder.

Bottom Pocket

Easy-access bottom pocket featuring a large opening on the wearer's right and trash port on the wearers left.

Sewn using Dyneema stretch fabric.

Dyneema Stretch Front Pocket

Made with Dyneema stretch fabric. Can hold 5L, not included in the total volume.

Removable Padded Back Panel

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

Adjustable Side Pocket

Our Forward-facing, deep and low side pocket design keeps your bottles secure while still being low enough to reach into whilst the pack is worn. Each pocket can keep 2 x 1L Smartwater style bottles secure, just tighten the elastic using the pull adjuster.

Each pocket features two drain holes to stop rain collecting in them.

EPX400 Base

The bases of all of our packs are sewn using this highly durable 400 Denier fabric in Black.

Haul Loop

This simple webbing loop is there so you can pick up and set down your pack without putting excess strain on the shoulder straps. Using this will extend the life of your backpack and keep your shoulder straps in good condition.

Whistle Sternum Strap

Elasticated, removable and height adjustable, on a long thru hike we recommend keeping it with the whistle facing down to prevent it getting blocked.

Front Zig-Zag Elastic

Removable and designed to be able to store a folded Z-rest or assist with air drying your clothes.

Roll Top Closure

The closure has a 15mm vertical side compression. The roll top can also be clipped together at the top (dry bag style) and the side compression clipped around the front of the bag to aid carrying snowshoes or maybe a huge packs of chips etc.

Y-Strap

The Y strap offers increased support for larger items like a bear can or sleeping pad when stored on top of the pack

Fixed Ice Axe Loop

Sewn-in loop to easily connect an ice axe or walking poles.

Vertical Side Compression

This connects to the Roll top closure to allow you to compress the load of the pack

The roll top can also be clipped together at the top dry bag style, and the vertical side compression straps clipped around the front of the bag to aid carrying snowshoes or maybe a huge packs of chips etc.

Load Lifters

These use daisy chain webbing coming off the shoulder strap to stabilise and adjust the balance of your pack while hiking.

Z Side Compression

Great for securing trekking poles, tent poles or drying your wet socks. The side elastic is adjusted using a Lineloc adjuster.

Sewn In shoulder Pocket

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.

FAQ

Does my torso size affect the volume?

No, In all of our backpacks the height remains the same regardless of torso size.

So a large torso pack will have the exact same volume as a small torso pack.

What is your refund policy?

Any unused off-the-shelf backpack or accessory can be returned to us for a refund, minus the shipping cost, up to 14 days after you take delivery of the goods.

Return shipping is at your own expense. If you wish to start a return, you must contact us first.

What import taxes will I pay?

Atom Packs is registered for VAT in the UK: GB329424790

All prices displayed in GBP (£) on our website will include VAT at 20%. If you are browsing our website from outside of the UK, you may shop in your local currency, in which case the price shown will be exclusive of VAT.

Customers outside the UK are not liable for UK VAT, however, you may be liable for your country’s import duties and tax.

Make sure you understand how much Customs Tax and Import duty you might pay before ordering - check out https://www.simplyduty.com/import-calculator/ for an estimate. This is a guide only.

The HS code for backpacks and accessories is 42022290

Do you ship internationally?

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

Full details on our shipping page.

What is a Lead Time?

The lead time is the estimated time between placing an order and it leaving our workshop. The lead time for new orders can always be found in the top banner on any page of our website.

If you have already placed an order, you will have received an email with an estimated shipping date, this date is still accurate unless we have emailed you saying otherwise.

Pre-existing orders can ignore any lead time updates to the website, this is relevant for new orders only.

What is the shipping time on a custom order?

We ship all of our backpacks using expedited couriers, however the item only ships once our lead time is completed.

In general shipping times by region are:

UK: 1-2 days (DPD next day)
Europe: 2-7 days (DPD EUROPE - depending on customs delays)
US: 2-5 days (UPS)
Rest of world: 1-2 weeks (UPS, DPD or Royal Mail, depending on location)

Why is base weight important?

This is a somewhat philosophical question, as, base weight has more significance the longer you are planning to hike.

In general, base weight gives you an indication of your level of packing discipline. (Remember, base weight is the total weight of everything non consumable that you will be carrying) There is no one correct base weight for each backpack, provided you are able to add enough food and water to remain under our recommended load capacity for your chosen backpack.

i.e. on a 4 day trip, along with your base weight, you would have to add 4 days of food (let's assume 1kg of food per day), to keep pack weight under 8kg total, you would need a base weight of sub 4 kg where as the same hiker on a 2 day trip could afford a 6kg base weight to remain under the 8kg total.

What is a base weight?

Your base weight is the total weight of all clothing and equipment that will be in your backpack while hiking. You should not include consumables like water, food, medicine or fuel.

i.e. the weight of an empty fuel canister can be considered for your base weight, but the fuel within it cannot.

What does recomended load capacity mean?

This is our best guess at what the average person could load into this pack while still being comfortable.

This is entirely dependant on your physiology so must be taken with a pinch of salt. i.e. If you are Chris Hemsworth (Thor... Phwoar!), you may well be able to carry more weight than, say, Gollum from the Lord of the Rings.

In general, we find our limits to be fairly accurate, however, If you find yourself nearing or exceeding the number listed with any regularity, then you should probably look at a more supportive pack from our range.

What can I change on this order?

This Atom comes with a fairly fixed spec, however if you wanted to change the elastics then that is a quick way to update or refresh the look of your pack.

(we do not recommend you replace the side pocket elastic unless it breaks as, it is tricky to do)

How long does it take to ship?

Atom Packs is a small team, we quote a 2 week lead time even on in stock items to allow us to make any hip belts or accessories that go with your order, this also allows us to adapt to fluctuating demand.

In general, we aim to ship out far sooner. If you want to know before ordering when your item will ship, please contact us.

Do I need to use a pack liner?

Yes, even though our materials are water resistant, the seams are not taped and thus water may ingress into the pack during extended rain.

Any items that you wish to keep dry must be kept in a waterproof stuff sack or liner.

Can I customise a ready made pack?

No, ready made packs are sold only as pictured, this enables us to hold them in stock and, thus, get them to you faster.

However, If you wish to customise an Atom, you can go to our customiser and build one your way!

Is it waterproof?

Our packs are not waterproof.

We use highly waterproof fabrics but we do not tape the seams. Therefore some water may ingress into the pack during periods of extended rain.

Customer Reviews

Based on 29 reviews
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Reviewer avatar
Knut
One of the best gear choices I've ever done

I've been having this pack for ~2 months and I totally love it. Reviewing it after hiking ~400 km with it, the longest trip was two weeks and 280 km in a row in Sweden. My base weight (including this pack) varies between 7,0 and 7,5 kg depending on the hike. Maximum load with water and food which I have tried with this pack was ~15 kg.

The whole story started for me when I've decided that I do not want to buy any US brand gear anymore and started a research for - ideally - Europe based alternatives. That brings me to the only downside of this pack which I can think about, and that's its availability. As soon as I decided that I want buying it, I went in touch with Atom Packs customer support and they were EXTREMELY helpful with providing information about when the next batch is about to be dropped and what to do to secure a pack. In addition, they helped me to ship the pack quickly after placing my order so while I was really nervous first about getting it at all and then about getting it in time, it has happened. Risking to wait and getting this pack was definitely worth the stress for me, but it is not for everybody - so if you decide to get one, do so a good time ahead of your trip. But here all the negative aspects end and everything else is shiny colours only and pink fluffy unicorns dancing a rainbow!

This is my very first UL pack (i.e. 40-50 liters below 1 kg) and I've chosen it over all its competitors after watching and reading many and many reviews. Must have for me were these features: roll top, bungee cords for attaching and drying equipment, shoulder pockets which fit my phone, bottom snack pocket, detachable hipbelt pockets, easily accessible side pockets while walking, selectable hipbelt size (with included hipbelt).This pack has all of these features, so it very soon became my primary choice which was later strengthen by independent reviews.

I was afraid about lack of a "proper" frame system of UL packs in general since I've never had one before, but it turned out to be an unnecessary concern when it comes to this pack - it is as comfortable as it can be given its weight and I was extremely positively surprised about this aspect! After wearing it couple of days and more than 200 km, I could barely notice it on my back. There was no shoulder or back pain at all, the pack just became a part of me and I had an extremely good time. Packing and unpacking it is a breeze and takes no time nor effort, eating snacks or accessing water without donning it off is no problem either, all the pockets and compartments have just the right size and placement.

When it comes to back ventilation, it is quite obvious - there is none. I am sweating a lot when hiking so that was another aspect which I was afraid of, but I just accepted it and I don't care anymore. I was sweating a lot while wearing ANY backpack, regardless its ventilation, so - does it really matter? Of course the pack gets smelly after couple of weeks on the trail, but it is very easy to clean it and get rid of the smell. I even received a video into my email box from Atom Packs with instructions how to clean it properly!

To sum it up, I never thought that something like an ideal backpack with no compromises exist, but it does - and it is this one. I would definitely buy it again and I will strongly recommend it to any hiker who will ask me. Thanks for your job and keep it up, I am grateful to the whole Atom Packs team! Departing to yet another hike with this pack tonight and looking forward to it.

PS: I personally don't care about colours and any other artistic design aspects at all, so I am not rating this.

A
Amelia
Best backpack

After alot of miles and about 300 days of solid use this backpack is still holding up amazingly well. It's compact but spacious, able to carry higher weights when needed and I like that it sits close to the body which is great for scrambling. I've taken this as my only bag for backpacking and trekking across south America (probably should have got a 60l to carry all the gear needed at times but made it work with the straps & that's on me) and various multiday hikes and camps across European mountain ranges. Ive also used it a lot as a day bag and you can cinch it in without being too baggy. Love it and would replace in a heart beat if it ever went missing.

M
Marius
Rugged, versatile and incredibly comfortable

I have used my pack for multiple trips in rough and wet terrain in Norway and the Austrian Alps. It doesn’t show a scratch despite having been rubbed against some sharp rocks. It’s super comfortable to wear all day, the hipbelt adjustment is perfect. If you leave most of your stuff at a cabin and only take the essentials up a peak, the pack compresses down nicely.
I have also used it to carry up climbing equipment, it’s no problem to strap a rope and helmet on.
I would recommend adding the hipbelt pockets, they are much larger than I thought an easily hold everything you want accessible.

G
Greg Milne
Great lightweight comfortable pack

Really enjoyed using the Prospector EP50 on a week's thru-hike (GR221), carrying ~5kg base weight + up to another ~4-5kg on heavy water carries. Handled heavy weights surprisingly well, with only a small issue with the back on heavier days (see below). Spacious enough to carry a lightweight 2-person tent, sleeping system, cooking system, food, water, clothes etc with space to spare. The double-buckle hip belt is great, feels like it can be fine-tuned to fit the specific shape of your hips. My other favourite features are the shoulder strap pockets (great for snacks on the go), spacious side pockets & bottom-side stuff pocket (which I used for rubbish in the small hole on the side and other bits on the larger side). The large inside pocket is spacious & the key clip useful for small things like keys, pocketknife etc. The front stretchy pocket was helpful for any bits & pieces for quick access. The mouldable back was a really nice feature. I found this worked really well overall. Once or twice (after some particularly heavy water carries) the back deformed somewhat and I had to take my bag off and stick a knee into the back to make it more comfortable. But I think worth it overall to be able to shape the bag to your back. Hopefully this doesn't become an annoying feature on a longer thru. I found the bungee cord to be super helpful for drying clothes on my bag while on the move. TBC how well they hold an ice axe, but could get my poles & clothes to be held sturdily.

My main qualm is I wish the bag had 1-2 more small pockets (possibly internal to the main compartment?) to help with organising gear better because it's easy to lose small items & get disorganised, particularly if you don't have many small packing cubes. Though this could be helped my adding hip belt pockets (which I didn't). Overall a really great pack that I'm looking forward to using on a longer thru later this year.

D
Darren
Great build quality

Great build quality and it’s really nice to support a UK company. It’s my first roll top backpack so I’m still getting used to that, I’ve had it out on 3 wild camps in the Lake District so far. I do find the chest buckle a little tricky to clip in but I’m hoping that will get easier with practice, also the hip belt buckle looks small compared to other rucksacks that I’ve had, hopefully I’ll never have an issue with it breaking.
Overall I’m very happy with my pack and I’m sure that the more I use it the more comfortable I will be with it Atb Darren