Zygos 5.0 Hydration Pack

(5 customer reviews)


Since the first iteration of the Zygos, tens of thousands of runners have utilized this high-capacity 14 liter race vest. The lightweight and comfortable wrap around design complimented by the ErgoFit Harness ensures the Zygos 5.0 will be stable, comfortable, and hindrance free. The pack’s MaxO2 Form adjustable closure system secures and adapts to the pack’s load. This innovative system can conform the pack to the body using a single pull. Similar to the MaxO2 Sternum, this system allows the pack to remain secured without impeding natural breathing. Featuring 8 on-the-go pockets there are 2 zippered shoulder pockets, a dual 4-way stretch mesh pocket, a pair of stretch mesh pockets (one of which is zippered and suitable for carrying a large cell phone), a zippered side pocket, and a magnetically closed side pocket. The main back compartment has been reinforced at the stress points with XT fabric which contains stronger than steel ripstop fibers. This pack includes a 2-liter reservoir that fits into the removable insulated bladder compartment. Available in 3 sizes to ensure a perfect fit.


  • Recommended Use:
    Versatile Pack utilized in any run scenario, training or racing.


    • Lightweight, soft, breathable, but strong, large-holed mesh pulls moisture away from the body to keep skin dry and cool.
    • Silicone and PU coated feather-weight nylon fabrics resist water, abrasion and tears.
    • Max O2 Form™ for unrestricted breathing while maintaining a stable pack. Uses shock cord with good stretch for unrestricted breathing but also good rebound on the stretch for a stable ride. Patent Pending.
    • Plush feeling micro-fiber polyester edges, soft and non-abrasive against skin and clothing.
    • Sweat proof webbing—won’t absorb water or get saturated and heavy.
    • Safety stitched bar tack on all stress points.
    • Quiet, bounce free, easy to see and use, zipper pulls.
    • Zig zagged stitching over elastic for ultra-durability, increased stretch and rebound.
    • Simple, fast, easy in and out bladder attachment.
    • Magnon pocket for sweat-free pills, with automatic magnetic closure for rapid access to pills and other essentials. Patent pending.

Fit:  Unisex
Size(s): Small (30″-36″), Medium (32″-38″) or Large (34″-42″)
Color:  Pitch Black
Hydration (included):  2L Reservoir
Bottle Compatible (not included):  UltraFlask, Formula 250, Human 20 oz 2.0, or Collapsible Bottle
Capacity: 854 c.i. (14L)

Additional information

Weight N/A
Dimensions N/A

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Fluid Capacity

2 L (70 fl. oz) Reservoir

Total Volume

14 Liters

Weight (Includes Reservoir)

16.0 oz (454g)


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5 reviews for Zygos 5.0 Hydration Pack

  1. Franck TJ (verified owner)

    The Zygos is very well designed, convenient, and looks durable. The volume to store food and stuff is great and enough for a 50-mile autonomous race. The 2 liters hydration pack is well kept in place and you can insulate it with a smart insulation layer (that can be removed). I noticed small details that make the difference. I like very much the Zygos. I ran 3 hours with it and was happy with the overall experience. I’m ready to go for the 5 hours run in my training plan confidently.

  2. Nathan Dorward (verified owner)

    I love the fit of this pack and the arrangement and stretch of the pockets. It’s the most comfortable vest I’ve ever worn right out of the packaging. Runs longer than 6 hours are no problem with this vest.

  3. Lori Pratt Smith

    The Zygos 5 vest is the best! The new front adjustment system works great and is so versatile. I have a very small torso, so fit of an my running vests has always been a problem. With this pack I moved the attached hooks to the levels that fit best for me and there is no bouncing weather pack is full or almost empty. Easy to tighten it while on the run too. I have used it for a pace duty at a high mountain 100 mile run and for a shorter race so far and has met all my needs.

  4. Daniel Hopping (verified owner)

    AMAZING product! This race vest truly has it all! Just finished a 30 mile training session and it far exceeded my expectations. Ton of storage areas, easy access to gear, insanely comfortable. The form fitting system is amazing as it adjusts to your body and moves with you. You will forget you are even wearing it at times. Just put it on right out of the package and get out there and log some miles! If you are looking at 30 miles or beyond, this is the pack you must own. I can’t wait to take this out on my 50 mile ultra in October and then my 100 miler in April. Thank you for an amazing product, keep doing what you are doing Ultraspire! Also, I highly recommend purchasing two Ultraflask 550 Hybrid bottles! They fit in the pack perfectly and the form of them molds right against your body in the pockets.

  5. Greg Ryan (verified owner)

    Perfect vest for long ultras that require lots of gear. Performed great for 35 hrs. in a mountain ultra.This vest can fit it all with perfectly placed storage options. The fit is very comfortable.Excellent, breathable material. I can’t imagine a better vest.

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