Synaptic Hydration Belt

(10 customer reviews)


The Synaptic Hydration Belt has a conical shape combined with front and back carrying capacity for a balanced load and a comfortable fit. This water belt is so balanced it won Ultra Running Magazine Top Pick for stability. Store a hat, beanie, gloves, jacket, or even trekking poles with 2 shock cords on the front pouch. The Synaptic hydration pocket is also interchangeable with the Lumen 600 2.0 light belt to suit custom hydration and lighting needs.

UltraRunning Magazine Top Pick!



ErgoFit Waist
Recommended Use:
Racing and training; 1 hour between refueling stops.


• Dual-sided adjustment for good sizing range with single speed hook access for taking waist belt on and off.
• Center front pocket is large enough for cell phone or energy foods with tuck away jacket straps perfect for extra clothing or Z-poles.
• Angled minimalist bottle holster for easy right handed access. Bottle rides close to the body for a comfortable stable ride.
• Synaptic is an MBS™ belt.  Back is compatible and interchangeable with a Lumen 600 front for a hydration and illumination combo.
• Small flat zippered pocket next to holster to secure keys or other essential items.

Fit: Unisex
Size: Universal
Color options: Luminous Blue or UltraRed
Hydration (included):  1 x UltraFlask 550
Capacity: 50 c.i.; .85 L

Additional information


Waist Belt



Fluid Capacity

550mL UltraFlask bottle

Product Weight (lbs)

Total Volume

34.2 c.i. (.56 L)


10 reviews for Synaptic Hydration Belt

  1. Tina

    I take this belt with me everywhere. Whether it’s a short walk or longer run. It holds just the right amount of water. I love that the bottle is so soft that I can suck out the air half way through and squish it down to reduce sloshing. I put my keys in the back zippered compartment. In the front, I like to carry my cards/ID (there’s two inner pockets for this). I always listen to my music and the front pocket fits my phone perfectly. I usually start my run out with a light jacket and then take it off and loop it through the shock cords on the front of the pack. Sometimes my jacket is heavier and I still don’t feel a bounce when it’s attached. It’s awesome!

  2. Kevin Zanker

    I absolutely think this is the best hydration belt. I liked my previous belt and did not like any of the alternatives until I found this one. No issues filling up a regular water bottle and having stability. I wear the belt for all my long training runs and races from 10K to marathon.

  3. Brian Horton

    Overall the belt fits comfortably with minimal bouncing. I did notice that on warm days when I am perspiring heavily, water does collect in the front pouch. Definitely use ziplock bags if you want items in the front to remain dry. Two issues with the pack. The first is the very small pouch to the left of the water bottle holder. It is virtually useless. I typically carry ID when running, the pouch is so small it will not accommodate my drivers license. The second issue is the loops designed to hold the excess belt. For reasons that escape me, the belt loop holders are stitched in place and can not be moved. If you have a larger waist, the excess belt material can not reach the holders and they just flop around while running. I would encourage Ultraspire to increase the size of the small back pocket and do not stitch the belt holder loops in place. Thank you.

  4. Naz

    A very good belt. Got the chance to use the belt for trail running. The belt secured to the waist with little to no bounce at all. My waist is about 27”, I noticed the belt is slightly loose but good enough though. I can say that its an excellent choice. Not like other belt that keeps on bouncing. Good job done by Ultraspire. I owned the speedgoat and now the synaptic waist belt. I will purchase all products from Ultraspire next time since they make good quality running belt. It did not disappoint me.

  5. Paul (verified owner)

    First, the Soft Flask has very good flow. Much more than a standard water bottle. Second, the belt holds well without being too tight or bulky.
    I have used it only Nordic skiing and for a few easy runs, but it worked well. It works better than any other belt I have tried(Amphipod, Salomon, old Camelbak). I took a chance on this one because I like the belt on my Lumen 600 so much.
    Last, the front pocket works well for phone and gloves.

  6. Giff

    Super comfy, incredibly secure, well ventilated and easy to dial in a perfect fit. The integration with the Lumen light series is a great bonus and the bungee system on the front is perfect for keeping a wind layer handy in the mountains. My only suggestion for improvement would be a slightly larger/stretchier front pocket to carry a bit more gear and/or a smartphone.

  7. Marjorie (verified owner)

    Better than any other waistbelt hydration system I’ve tried. Stays in place, easy access water bottle, holds the things I need on a trail run. It’s a superior product.

  8. Lance

    Love this belt. Was a vest guy for the longest time on all distances, and then switched to handhelds, but really didn’t want to have something im my hands for hours. The synaptic is that perfect 50k hydration solution, and honestly would work just as well with any distance with aid stations at least every 7-8 miles max. Holds a good amount of gels in the front pocket, and i like that there are two smaller open pockets inside of it to store pills separately. The bounce of the belt is nearly zero, and it sits in the perfect spot in my opinion to avoid messing with hip mobility. Definitely appreciate that the bottle holder maintains its form, which makes it super easy to get the bottle back in. In most cases it’s my new “go-to”.

  9. Sharleen Stevens (verified owner)

    This was my first hydration system from UA and I’ve been using it for three years! I love it. I’ve used it from half marathons to my first 100 miler and all the training in between. It was perfect for that 100 miler because it was 20 mile loops, so I could keep an eye on the amount I was drinking (versus a reservoir) and I had plenty of stations for easy refills.
    I love the comfort and fit. It does not bounce and I don’t have to readjust after running hills like my previous belts. The main pocket fits my phone, card, and nutrition. I use the small pocket by the bottle for my key or to stash meds during a race. I can’t say enough good things about this belt. Now I just need to find a reason to try to carry my poles on it.

  10. Noland Tipton

    This is my first hydration belt. I tried on a couple different belts from competitors at REI but the store I was at did not have the Synaptic in stock so I had to take a leap of faith and trust the reviews I had read and I am glad I did. While I did not run in the others, this one was more comfortable as soon as I put i on. It rides well, is secure, breaths well, and is easy to adjust on fly the if need be without stopping or really breaking stride. I like how the bungees on the front will tuck back into the pocket so they do not flap around when not in use and the front pouch is big enough without being so big it is in the way. The hook that holds it on is a much better design than the typical plastic clip buckle. If it wasn’t for the sound of the water sloshing in the bottle I would forget I was wearing it. I let a training buddy wear it on a shorter run just to test it out and I am pretty sure he has already ordered one of his own.

    My only issue was the bottle I received had a small defect in the caps molding resulting in a leak. I emailed Ultraspire about the issue and received a response within hours. Email response was not only quick, but very friendly and apologetic that my bottle leaked a little and they promptly took care of me are sent out a replacement cap. Great belt and great customer service.

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