We are increasingly seeing walking packs that draw on the close-fitting and highly breathable design of a running vest, blurring the boundary between these categories. In my view there is nothing not to like about this. Whatever pace you're moving at, a light, airy and well-balanced pack is always going to be an advantage, particularly if it offers quick and easy access to drinks, snacks and other wee bits and bobs. The Nitron 25L is a great example of the style.

In Use

This is a versatile little pack. While primarily designed for day walking, the Nitron 25L has a close and well-balanced enough fit to be used when running too, with broad body-hugging vest-style straps that make for zero bounce. If you were on a fast-and-light minimalist overnight or a mountain marathon type event it might be worth considering. Giving full freedom to the arms, it also works well for scrambling. Because it sits high on the body you could even wear it with a harness while multi pitch rock climbing, though slightly mitigating against this is the fact that the inbuilt hip belt is not fully removable, and doesn't secure that well when wrapped around the pack.

Thanks to its perforated straps and back padding the Nitron 25L feels light and airy, offering loads of ventilation and minimal sweatiness. In summer weather it's a joy to wear. When it comes to mountain use it would be great in all but full winter conditions, when the lack of ice axe attachment points would be an issue.

While 12L and 18L versions are also available I find the 25L capacity spot on for single hillwalking days. In addition to the main pack the multiple external pockets really help boost the amount you can carry, as well as the convenience of accessing stuff. Being able to drink and reach for snacks on the go without having to stop and remove your pack cuts faff time, which is great for smooth efficiency whether you're running or just walking with purpose. It's also nice to be able to stash hat, gloves, phone and a shell on the outside of the pack, keeping all the essentials close to hand.

Weight

At 611g in size M/L the Nitron 25L is lighter than most walker's packs, albeit not to the skimpy levels of some more running or climbing-oriented specialists (Rab's Veil XP for one). In this case shedding weight doesn't mean making it flimsy; the nylon ripstop fabric feels tough, and general build quality is high.

Fit

The Nitron pack is a unisex model, coming as a fixed back length in a choice of two sizes, S/M (46cm) and M/L (48cm). Even the longer version is pretty small. Taller users will find the hip belt does not sit anywhere near the hips; at 1.83m tall, scarcely a giant, I find it more of a belly belt. It's not necessary to have a belt for load bearing in a small-ish day pack, and I tend to remove them where possible. That doesn't work in this case, because even though the nylon belt webbing can be detached, the wrap-around hip pockets cannot. On the plus side, while the belt bears no load for me, it does add some stability. The shoulder harness is built on small dimensions too; I can get by with it, but anyone taller or broader than me will struggle.

Made of a breathable mesh, with only minimal padding, the broad shoulder harness hugs the torso, combining with the soft back (a pack this small needs no frame) to give you a superbly close fit, with no shifting or bouncing - equally good whether you're running or scrambling.

The fit is fine-tuned with two stretchy height-adjustable chest straps. On a very small pack or running vest elastic chest straps make sense since they help you get a lungful of air and move freely; however as the weight you carry starts to increase the shoulder harness has to do more work, and a stretchy chest strap can start to feel as if it has too much give. If you fill the Nitron 25 to capacity I think you're on the cusp of that being an annoyance.

Features

The main zipped entry opens wide for easy access; you also get a small zipped valuables pocket (with the essential key clip) and a hydration bladder sleeve.

Learning from their excellent running vests, Rab have really gone to town on stretchy external pockets - and I love them! Stuff them all, and you can carry significantly more than the pack's nominal 25L capacity.

The zipped hip pockets are really generously-sized, with plenty of room for thick gloves or even something as substantial as a light softshell. On each side is a stash pocket that'll hold a pair of folded poles or a 1L water bottle. And on the front of the pack you get a big stretchy sleeve that's perfect for wet shell layers or a map case.

One shoulder strap sports a sleeve for a soft flask (not included). I use this all the time, and wish all packs (even climbing packs) had at least one. With the Nitron 25 I find the soft bottle sits very high on the shoulder, making it quite hard to drink from on the move; this may be thanks to the relatively small size of the chest harness on me. On the other shoulder strap is a zipped stretchy pocket that's ideal for a phone, a compass or some snacks.

Walking poles can be attached to the harness runner-style (it always feels as if I'm going to impale myself with these!) or more conventionally via the side pockets.

The verdict?

A lightweight day pack with a superb running-inspired harness, the Nitron 25 is close-fitting and highly breathable, making it ideal for all summer hill fun from walking to running to scrambling. With a wealth of handy external pockets, it's great for accessing the essentials on the go. For those with a smaller frame this little pack looks hard to beat; in fact our only complaint is that Rab don't offer a longer back length for larger users.