This new pack by Montane comes with an interesting ‘ingredient’ called Polygiene. It’s something we’ve written about a fair few times, having included it in the last few Outdoors Magic 100 series – in the Rab Neutrino 600 sleeping bag review for instance. In case you’re not already familiar with Polygiene, it’s a special, permanent chemical mixture – bonded within fabric fibres – that’s able to kill-off odour causing bacteria brought by sweat. And it genuinely works.

While plenty of jackets, socks and sleeping bags come with it these days, this product by Montane is the first ever pack to feature it. And we find this pretty surprising, bcause when you’re running in hot weather, the back of your pack is going to get almost just as sweaty as your t-shirt, right?

The Montane Via Fang 5 is a pack made for long distance, single day running on mountain trails. With its 5-litre capacity, you can expect to be able to carry at least two water bottles (it comes with two squishy ones), a lightweight waterproof jacket, a midlayer, your wallet, phone and a bunch of snacks.

On the pack itself there are two main zipped compartments, two stretch mesh pockets on the kidneys that can be accessed while on the-go and an external bungee for compression or for stowing a jacket quickly.

The harness has a number of different quick access options. On the strap on the right shoulder there’s a small zipped stretch-mesh pocket big enough for a phone, then a long stretch-mesh pocket to stow a bottle. On the strap on the left hand side there’s a long zipped pocket capable of holding another water bottle or as many as five or six energy gels, then there’s a smaller stretchy mesh pocket with an elasticated closure to keep stuff inside it.

“This pack fully enables you to run naturally and comfortably.”

If you run with poles there’s a really handy way of stowing them on the go. You simply slip them through one toggle on the left hand shoulder then behind your back and through another toggle near your right elbow – a kind of diagonal arrangement.

The harness adjustment Montane have come up with is very clever. First of all, around the stomach there’s a long and stretchy Velcro strap that involves absolutely zero pfaff to get a comfortable and secure fit that moves freely with your breathing. Then there’s a stretchy sternum strap that can be clipped/unclipped and adjusted quickly and easily.

We’ve probably mentioned the words ‘stretch’ or ‘stretchy’ about 10 times in this review already, and this reflects the unrestricting fit of the whole bag itself. It fully enables you to run naturally and comfortably.