Review: Ultraspire Isomeric 16oz handheld hydration

Ultraspire Isomeric 16oz
Ultraspire Isomeric 16oz

I’ve been running and holding water bottles from day one. I used to take water with me on the shortest of runs but as my knowledge and experience increased I realised I only really needed to carry it past 10km or if I’m going to be out, running at any pace, past an hour in hot weather.


For a good while I stopped taking water on any runs as I was getting annoyed with my hands cramping up over distances after holding on to solid plastic bottles. I thought I’d got around this when I discovered Salomon’s soft flasks. Although they are a bit more comfortable to run distance with you still really do have to have a hold of them so I needed to find a solution for my longer runs and races!

I had a little look around to see if I could get a soft flask holster but the Salomon specific ones were too expensive for what amounted to a piece of fabric and a couple of pieces of elastic! I wasn’t sure if the Inov8 ones would be compatible so I decided to look at other brands. I took a long, close look at Nathan offerings but they seemed a little bulky with most of their handheld systems incorporating stash pouches and pockets so I discounted those as an option and went hunting through Ultraspire’s selection.

The Isomeric handheld is ideal for half marathon racing and marathon training long runs as it hold 500ml which is enough over the distances you might cover between 21km and 42.2km – personally I don’t carry water during marathon races and prefer to grab a bottle or cup from the aid station but for quicker half marathon racing I like having my own water to hand so I don’t have to slow at all! I will most likely carry this during my first 40 mile ultra in August even though it’s on a lapped course – I figure I’ll be able to drop it with my crew (read: girlfriend) on the first lap and exchange it for a soft flask and then pick up the refilled Isomeric on the second lap thus curtailing any need to stop or slow through the aid station.

I will say that it took some time for me to figure out how to hold the bottle properly as it is not a shape I have encountered before being rectangular and sitting across the palm. It also took some time to figure of the best way of twisting the nozzle to a drinking position without losing some of the contents to my shirt, shorts or the ground and I still struggle to open and close it quickly with sweaty hands moving at anything above easy pace! But if you’re looking for a minimal piece of kit that will save you from having to hold on tight, expending energy as you do so, then this would be the thing I would recommend at this point. Certainly though, I will be trying out other handheld systems to see how they shape up for me personally.


  • Minimal/No frills
  • Easy to adjust
  • Quick drying
  • Comfortable once you find the right tightness for your hand


  • Not easy to drink from at anything over easy pace
  • Difficult to open and close nozzle with sweaty hands
  • Would recommend the smaller bottle for those who consume less on the move or who have smaller hands/handspan as 16oz model is quite large
  • Took a while to get used to shape of bottle as it is rectangular and flat

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