If you're an endurance athlete who needs a comfortable hydration solution as well as storage, the new Kalenji Bag Trail 5L Hydration Pack is the perfect choice. We give our verdict on this lightweight running hydration bag.

Kalenji hydration bag running trail pack hydrtion vest

Comfort - 10/10

When running, especially over long distances, you want to be as comfortable as possible and to make sure nothing on you is going to start chafing after a few hours. This hydration vest is very comfortable and secure and does not chafe or rub in any places. It features two adjustable straps to the front to keep it in place and overall it fits very well. The bag doesn't bounce around at all as you run and the straps feature a felt lining which is very comfortable, meaning it doesn't rub your arms if you're wearing a running vest.

Small details really make this hydration bag great, such as grippers to the holders where you place the water bladder mouthpiece so it doesn't move around and stays put during your run. The mouthpiece itself is very easy to use – just twist and drink. This means that even with slippery, sweaty hands you can still access your water! A problem I've struggled with in the past with other hydration vests.

Sundried Kalenji running hydration bag review

This hydration vest comes with a 1L water bladder which fits easily inside.

Storage - 9/10

For such a low-priced 'basic' product, this hydration pack has a fantastic range of storage options. There are two pockets to the front which you can access easily while you're running. One is designed for a 150ml soft flask but you could put anything small in there – keys, snacks etc. The other front pocket is large enough for a smart phone which means easy access and practicality while running. To the rear of the bag there is a 'kangaroo pouch' which is designed for packing away a running jacket in case you might need it which is brilliant. I use it for a sweat towel because my hands get so sweaty when running in the summer! This is really useful to be able to carry as I hate having wet hands while I'm running and means I can dry off if it starts to rain too.

The pack itself comes with a 1L water bladder which fits perfectly into the space and it's easy to get it in and out to fill it and empty it. The straw/mouthpiece weaves out of the back and in front of you across your chest. There is also a safety whistle attached to one of the pockets which is a nice touch, especially if you do lots of trail running in remote locations.

Kalenji Bag Trail Running Hydration Vest Review Sundried

The safety whistle is tucked into the side pocket. I never would've realised it was a whistle if I hadn't noticed the description on the website.

There is also an inner zip pocket which Kalenji say is designed for your smart phone or keys but I would always be weary that due to possible unexpected leaking from the water bladder, anything going into this pocket has the potential to get wet.You also can't access this pocket while running so you wouldn't want to put anything in there that you need before you stop. 

The only reason I marked down the storage is because the 150ml soft flask pocket is a little awkwardly designed and could do with being bigger so that I could get a larger flask in there as 150ml is little more than a gulp! However, other than this very small quibble, the storage on this bag is exceptional and more than ample. 

If you're in need of slightly more storage, the 10L version of this bag allows for two 500ml soft flasks in front pockets as well as space for more snacks and even walking sticks. 

Kalenji running vest hydration bag Sundried review

Price - 10/10

With an RRP of £17.99, this brilliant hydration bag is less than half the price of similar products and is even 60-70% cheaper than some higher end hydration bags from the big players in trail running and endurance gear. When shopping around for a new hydration bag, I was really rather shocked at the sky-high prices of some on the market. A similar product from big brand Camelbak will set you back over £60, some Salomon hydration vests are over £100 and the singular offering from Nike, which is a very basic product, is priced at £75.

Kalenji offer a really accessible, reasonable price which is perfect for first-time endurance runners or trail runners who have never bought a hydration vest before so don't want to shell out on something expensive, but also for experienced runners who just don't feel like spending £60+ on a hydration bag! Considering this product provides everything you need, the price is almost too good to be true.

hydration bag review Kalenji Decathlon Sundried

The mouthpiece is leakproof thanks to a silicone bite guard and twists on or off for easy use.

Verdict - 10/10

I'm hugely impressed by this running hydration pack and wouldn't consider any other on the market. For someone who regularly runs half marathon to marathon distance both on the road and on the trails, it provides the perfect amount of storage and water. I'd use this for anything up to 50km/31 miles in distance in all weathers for both training and racing.

For any endurance events that are further in distance or more remote in location, perhaps a larger bag would be better as you could take more supplies. However, for organised races and training runs up to marathon distance, this hydration bag is perfect in every way for beginners right through to experienced runners.