OK, so I have been fortunate enough to have a few of the UD Signature Series packs over the years. I started off with the Scott Jurek version one (the red ones), then reviewed the larger Pete Bakwin version 2 (the blue ones) and finally have one of the 20l fastpacks which is my go to pack for run commuting or when I need more gear.

All of these packs evolved and Ultimate Direction are a company who take customer feedback seriously and act on it. Consequently whilst you see a few other packs here and there during an ultramarathon, I think its fair to say that between Ultimate Direction and Salomon, they have the majority of the field covered.

Last August a friend of mine who had recently received sponsorship gave me his old Salomon race vest and I used this during UTMB and the Cotswold Way Century (both DNF’s incidentally but not anything to do with the pack!). It was a great bit of kit and the soft flasks were a real asset over the previous hard bottles used by Ultimate Direction. That said there were some flaws including the size of the pockets and access to the rear when using a dry bag, but overall I thought it slightly out-did the UD packs…just.

And then this came along…and its blown all past UD vests out of the water as well as addressing all of the faults I had come up against on the Salomon race vest. I honestly cannot think of an area of the vest that I could suggest an improvement on.

To start with, the pack is lighter at just 400g (14oz) yet the AK’s biggest weakness always was its capacity which was tiny. This has now grown to 11.5l which competes with the larger Salomon packs. The vast majority of this storage is now in the large rear pocket which features one zip which travels along the top and all the way down the right hand side. This means the pocket is much easier to open and access gear or stuff a dry bag. I tend to do the latter as no pack is fully waterproof and dry bags are very cheap. These are perfect for mandatory kit you don’t plan to access unless essential.

In front of this pocket is a large elasticated stuff pocket which is ideal for a waterproof to be quickly accessed but also has room for a base layer, hat and gloves ( or an ideal place to store a bladder if you prefer to bottles without hindering your mandatory gear). Finally you have the bungee area which can also hold extra gear.

Moving to the front, you have a new system to fit poles on the front which makes mountain races so much easier. At UTMB I didn’t ever fold my poles away as I was conscious of time taking my pack on and off to do this, but now you can access whilst the pack is still firmly strapped on and they don’t hinder arms whilst running.

The pack has extra storage on the front including a huge mesh pocket on the bottom left side. I drink a lot when running long distance and often find two bottles isn’t enough, but I don’t like bladders, so this expandable pocket is ideal to securely store a third (or even fourth) bottle.

The pack comes with two 500ml 2017 softflasks as standard and has increased space for a larger smartphone on the front pockets too. The side zipped pockets, which on previous versions I said you needed to be able to dislocate your arm to access on the run, are now lower and much easier to access.

Yes, I received this pack to review for free, but if I had to choose any pack on the market right now, it would be this one. It is expensive and I can’t talk for its longevity yet, but if built as well as or better than the older vests I have, which I still use, then it should be very sturdy indeed. For me, the key with this pack is versatility. It has more than enough capacity for big mountain races, but also using the bungees you can synch it down and carry the bare minimum for shorter races or training days out. The material is the softest I have comes across in a race vest and whilst my longest session so far was for 7.5 hours, I had no chafing or soreness when I returned.

Its truly a pack for all scenarios (bar multi-days or the Spine etc, before I have people tell me that!)

You can watch Anton Describing the pack here and you can buy the pack in the UK here

The pack comes in three sizes and all measurements are spelled out on the above links so you get the right fit.