This review of the Atom Packs Nanu X25 (21 oz / 600 g, MSRP: $269) examines a multi-use daypack with the potential to function as a one-night overnighter. The Nanu X25 is constructed with X10 Cotton Duck Fabric, 500 denier nylon, Dyneema Composite Fabric-reinforced stretch material, and triple stitched and bound seams.

Ryan Jordan talks about minimalist backpacking concepts and Atom Packs Nanu X25 features and specifications in the following video:

YouTube video

The X25 won’t replace anybody’s multi-night pack, and I don’t see it excelling in fastpacking applications (the relatively heavy material choice and shoulder-strap designs preclude it from that). But with a blend of bike, commuting, and backpacking specific features, it could replace two or three packs on the low-volume end of a backpack quiver.

This is a first look at new gear that recently entered our review pipeline, and hasn't yet been subjected to rigorous field use. Learn more about the types of product reviews we publish.
a red and black atom pack against a white background
Atom Packs Nanu X25. Photo: Atom Packs


  • clean, minimal aesthetics
  • body fabric: X10 Cotton Duck
  • back panel and shoulder strap fabric: 500d nylon
  • pocket fabric – Dyneema Composite Fabric stretch
  • classic overnight pack design – roll-top closure, three pockets
  • shoulder-strap pocket
  • padded laptop sleeve
  • removable sternum strap
  • triple stitched and bound seams
  • zip upper pocket with internal key clip
  • shock cord compression tensioners
  • shock cord trekking pole attachments
  • bike light loop

Testing Context

I tested the Atom Packs Nanu X25 on a couple of day hikes in the Tahoe Basin Land Management Unit (the traditional land of the Wašišiw people). Leaning into the Nanu X25’s intended use, I also ran some bike errands with it – to the grocery store, to the coffee shop to do some work, and to the post office. I didn’t push the Nanu X25 to its limits as a one-night overnight pack, but Backpacking Light founder/owner Ryan Jordan did, and I tap into his experience in this review as well.

A man wearing the Atom Packs Nanu in addition to a great hat walks away from the camera along a forested road.
Testing the Atom Packs Nanu X25 on a day hike in the Tahoe Basin. Photo: Andrew Marshall
This is a first look at new gear that recently entered our review pipeline, and hasn't yet been subjected to rigorous field use. Learn more about the types of product reviews we publish.

First Impressions

Fabric and Aesthetics

Atom Packs deviated from typical ultralight fabrics with the Atom Packs Nanu X25, choosing the relatively heavy X10 Cotton Duck by Dimension Polyant (DM) for the main body and 500 denier nylon for the back panel and shoulder straps.

DM’s X10 Cotton Duck is interesting. It’s a 100% cotton fabric with polyester X-PLY yarn reinforcements at 22 degrees off the warp and a polyester film laminated to one side. The upshot is a fabric that looks and feels traditional (think Carhartt jackets) but performs at a high technical level (extremely durable and waterproof, if not the lightest thing around).

An Atom Packs Nanu X25 rests on the forest floor
The Atom Packs Nanu X25 is made of durable materials. Photo: Andrew Marshall

X10 Cotton Duck started showing up in bikepacking bags because – I imagine – it’s not going to tear the first time it rubs up against a thorn bush at 20 MPH. So it makes sense that Atom Packs would choose it for a pack they assume you’ll be biking around with (more on that later). Based on my experience with and knowledge of fabrics, I have to assume the Atom Pack Nanu X25 is going to age beautifully in a way that synthetic fabrics don’t. And from a purely aesthetic standpoint, the pack succeeds right out of the box. X10 Cotton Duck seems to come in the kind of pleasing, toned-down natural colors I’d prefer to see more of in technical gear (please spare me more neon shades of green, blue, and pink).

I should note that DM has discontinued X10 Cotton Duck. I reached out to Atom Packs to see what they’d make the next run of Nanus out of (currently slated for sometime this summer). The answer is – they aren’t sure. It will be interesting to see if they stick with a natural fiber + laminate model (X-Pac has a variation called X11) or move towards something a little more traditional. The fabric choice adds a lot of character to the Nanu, so personally speaking, I’d think of it as a loss if Atom Packs went with something purely synthetic like ECOPAK.

a man wearing the Atom Packs Nanu X25 and, as previously stated, a very good hat, walks along a gravel road in a stand of aspens.
The Atom Packs Nanu X25 is essentially a miniature version of a classic three-pocket ultralight backpacking pack. Photo: Andrew Marshall

As a final nod towards durability, Atom Packs opts for a Dyneema Composite Fabric-reinforced stretch material that is likely to hold up well against rips and tears. This fabric choice seems a good compromise between the utility of traditional nylon stretch pockets and the durability of open-weave mesh.

Multi-use feature set

The Atom Packs Nanu X25 is essentially a miniaturized version of a three-pocket ultralight pack. It has a roll-top closure with a g-hook tensioner and a single over-the-top webbing strap. There’s a stretchy shoulder-strap pocket on the left-hand shoulder strap that’s big enough to accommodate my iPhone 12 Pro Max or my 650 ml water bottle.

The Nanu X25 also has a shock-cord trekking pole attachment system and two shock-cord compression tensioners on either side of the upper pack. This classic ultralight backpacking feature set gives the Nanu X25 the chops for all-day excursions and quick one-night overnights – provided you have a low-volume kit. A stiff foam back panel lends just a touch of structure, while a line of daisy chain webbing running down each shoulder strap provides attachment points for other incidental gear.

an Atom Packs Nanu X25 sits on a rock outcropping with mountains in the background.
The Atom Pack Nanu X25 on a day hike in Colorado. Photo: Ryan Jordan

The side pockets are cut at an angle. Usually, this design choice denotes a nod towards on-the-go accessibly. I almost never find such pockets practically accessible, and the pockets on the Nanu X25 are no different. It’s possible to fish a water bottle out of them with some contorting, but why bother when you’ve got a shoulder strap pocket right there?

Additional features expand the Nanu 25 capabilities beyond backpacking and hiking. There’s a zip pouch right above the shoulder straps that includes an integrated key clip, a laptop sleeve padded out by the foam back panel, and an internal pocket with a snap closure. A webbing loop sewn into the fabric below the rear pocket provides a handy bike light attachment point. These features make the Atom Packs Nanu X25 an attractive option for the user wanting a day pack that performs at a technical level while also doubling as a commuter or travel pack.

Construction and finish quality

The Atom Pack Nanu X25 features seams that are triple stitched and bound. The hardware and webbing loops are bar-tacked into place. Between these construction choices and the material choices discussed above, I’d classify the Nanu X25 as overbuilt, and I mean that in a good way.

In his Performance Review of the Atom, Dan Durston gave Atom Packs high marks on some, but not all, of his finish quality metrics. Looking over his observations and comparing them to this pack, I’d say Atom Packs has upped its game. There’s one line of stitching with a little wiggle – nothing the average user would be likely to notice.

Final Thoughts

There’s a lot to love about the Atom Packs Nanu X25. It’s a technical pack that doesn’t look or feel like a technical pack. It’s got just enough volume to make a low-volume overnight trip possible but maintains a sleek design that rides comfortably while hiking or biking. The aesthetics are enhanced by attractive material choices that also happen to be durable and waterproof. The overall construction is well-realized.

A man and a dog stand in a snowy meadow looking out at a vista of snow-capped mountains.
If you are wondering where the hair that covers the pack in the rest of the photos came from, your answer is in this picture. Photo: Stephanie Jordan.

It is, unfortunately, pretty expensive for a day pack, coming in at ~$269 at the exchange rate as of this writing. That kind of price tag is likely to be offputting to anyone with a daypack that is still doing the trick. But if you happen to be in the market for a new daypack and you’d like it to be one that can replace a few of your other bags as well, you could do worse than considering the Atom Packs Nanu X25.

Atom Packs is out of stock at the moment, so you’ll have to look around on the second-hand market to purchase one. Atom Packs tells me they’ll be tackling another run of this pack sometime in the summer of 2022.


A close up of the Atom Packs Nanu front pocket.
Dyneema Composite Fabric reinforced stretch pockets are a good middle ground between the stretchy functionality of normal nylon mesh pockets and the durability of open-weave net-style pockets. Photo: Andrew Marshall
a close-up of the Atom Packs Nanu X25 shoulder straps.
A line of daisy chain webbing runs down the center of both shoulder straps. Photo: Andrew Marshall
A close-up of the fabric used in the Atom Packs Nanu X25
X10 Cotton Duck is a hard-wearing, waterproof fabric with a very traditional look and hand-feel. It is certainly heavier than the sorts of ultralight fabrics commonly used in packs at the moment. Photo: Andrew Marshall.
A close-up of the top pocket on the Atom Packs Nanu x25
The Atom Pack Nanu X25 features a zippered pocket directly above the shoulder straps with an integrated key clip. Photo: Andrew Marshall
a close-up of the side of the Atom Packs Nanu X25
Features include: roll-top closure, adjustable shock cord compression on either side of the pack, and a trekking pole attachment system. Photo: Andrew Marshall
A close-up of a webbing loop at the bottom of the pack.
This webbing loop, which is more on the side of the pack than the bottom when the pack is full, is designed to clip a bike light to. Photo: Andrew Marshall
a close-up of the Atom Packs Nanu X25 side pocket.
The side pockets are pretty small but large enough to accommodate water bottles of the tall and skinny variety. Photo: Andrew Marshall
A medium shot of a water bottle in a shoulder strap pocket.
The shoulder strap pocket is a much better location for water bottles than the side pocket.

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