Atom Packs The Roo Review

Overview

The Roo is a lightweight hip pack (or “bum bag,” as Atom Packs proudly calls it) from a cottage gear company hidden away on a farm just outside of Keswick in the UK’s Lake District. It’s designed to be used either on its own or as a complement to your backpack when out hiking — in town or on trail, you decide. At 70g, it’s aimed squarely at ultralight and thru-hiking crowds who want quick-access storage without meaningfully denting their base weight.

Key Specs

Spec	Detail
Weight	70g (2.5 oz)
Volume	1.5L / 2.5L (two sizes)
Max Waist Circumference	120cm / 48 in
Main Zip	5mm YKK AquaGuard
Water Resistance	Water-resistant fabrics + AquaGuard zip; not seam-sealed
Strap	20mm soft-feel nylon with side-release buckle
Side Panel Depth	5cm / 2”
Fabric	EcoPak / XPac production offcuts (Zero Waste) or all-black RE version
Comparison	See how The Roo compares to similar gear

Performance

Weather Resistance

While the seams aren’t taped, the Roo is crafted with waterproof fabric and features a waterproof zipper, providing excellent weather resistance — and in both a rain simulation and dunk test, it kept moisture out and gear dry.

That’s a meaningful result, though the caveat is real:

the Roo is built using waterproof fabrics and uses an AquaGuard zip, but it is not seam-sealed, so some water could ingress in heavy rain — you should always protect your electronics.

For most conditions short of a sustained downpour, this is a non-issue. For a multi-day in the Scottish Highlands, throw your phone in a small dry bag just in case.

Organisation

The 1.5L version offers practical organisation well-suited for its size — the large main compartment includes an envelope-style security pocket, perfect for storing IDs, bank cards, or other small essentials, along with a convenient key clip.

A stretchy outer mesh pocket surprised testers with how much it could securely hold, and its rolled seam ensures that items won’t slip out, even during vigorous movement.

In practice, users have fit a phone, sunglasses, lip balm, sunscreen, snacks, and a wallet in the 1.5L without much trouble.

One outdoor filmmaker reported that the large size easily accommodated a drone remote controller, phone in the front stretchy pocket, midge net, sunscreen, keys, an ultralight wallet, and lip balm.

For the 2.5L version, the increased capacity may leave some room for improvement in organisation — Atom Packs cleverly designed the Roo so that the only significant change is the depth of the pack, so as long as you’re strategic with your packing, finding your items in either size shouldn’t be a problem.

Usability

The colorful, stretchy shock cord on the dual zipper pulls reduces strain on the zipper and makes it easy to open and close, even with one hand.

That’s a small touch that pays off every time you’re moving and need to grab a snack or your phone without stopping. One area where the design falls slightly short:

there’s no strap keeper to manage excess webbing once the belt is adjusted, which would benefit smaller hikers by securing the slack and preventing the strap from dangling.

On pairing with a larger pack: the Roo is designed for both standalone use and pairing with larger packs — though when using it with a larger pack, consider one without a hip belt or be prepared to wear two belts simultaneously. That’s not a design flaw so much as a physics problem, but it’s worth thinking through before you buy if you’re running an Atom Packs Prospector or similar hip-belted pack.

Build Quality and Materials

The Zero Waste version is made sustainably from EcoPak or XPac offcuts leftover from Atom Packs’ full-size custom backpacks — each fanny pack features unique colors that would otherwise end up in a landfill, which not only reduces waste but gives each pack its own distinct look.

The material is solid and will last a long time. Multiple reviewers independently praised the stitching quality, and the brand’s reputation for careful construction — built from

founder Tom Gale’s background as a triple crowner and professional mountain leader with over 12,000 miles under his feet

— comes through in even this small accessory.

Pros & Cons

Pros

• 70g is genuinely ultralight for a structured hip pack with this much organisation
• AquaGuard zip + waterproof fabrics held up in real-world rain and submersion tests
• Stretchy front mesh pocket is more capable than it looks
• Internal sleeve pocket and key hook cover the daily-carry essentials neatly
• Zero Waste construction is a genuine sustainability win, not just marketing

• Build quality rivals that of larger manufacturers while maintaining a trail-forward design with a small business feel

• Available in a solid all-black RE version if the random-color lucky dip isn’t your thing

Cons

• Not seam-sealed — not the right choice for serious rain exposure without extra protection for electronics
• No strap keeper for excess webbing; a minor irritant for those with smaller waists
• Random color assignment on the Zero Waste version (no way to request a specific colorway)

• Atom Packs is based in the UK, so warranty and service may take longer than with domestic brands

  for international customers
• The internal sleeve pocket is on the smaller side — one reviewer noted it wasn’t quite large enough to comfortably fit a passport

Who Should Buy This

The Roo is a strong pick for ultralight and thru-hiking enthusiasts who want genuinely fast access to trail essentials — phone, snacks, lip balm, keys, cards — without bolting heavy hip belt pockets onto their rig. It’s a natural companion to any hipbelt-free frameless pack, and it works just as cleanly as a standalone fanny pack for travel days or short hikes. If you’re already deep in the Atom Packs ecosystem and want a matching accessory, the RE Black version can be customized to match your main pack. Skip it if your main pack already has a substantial hip belt and you’re not keen on doubling up.

Verdict

The Roo does a lot right for 70g. The combination of a waterproof zip, capable stretch pocket, internal organisation, and bomber build quality at this weight is genuinely difficult to find elsewhere in the category. The lack of seam sealing and missing strap keeper are real but minor gripes that don’t undermine the core case. It earns an 8.5/10 — one of the cleaner lightweight hip pack options out there, especially if you value buying from a small, craft-driven operation that sweats the details.