Zygos 4.0 Hydration Pack (New!)

Rated 5.00 out of 5 based on 2 customer ratings
(2 customer reviews)


Bryce Thatcher’s pack of choice, the Zygos 4.0 hydration pack is very versatile. This pack is lightweight and high capacity, a comfortable wrap around style with full compression allow for the lowest profile empty or fully loaded. The Zygos 4.0 comes with a 2L reservoir and a magnetic clip to keep your hands free. New expandable mesh on the back panel gives 4 liters of extra capacity as well as storage in the front with extra pockets. Whether you are fastpacking, mountain biking, in a fast race, ultra race, or summit assault this hydration backpack is the solution for any athlete. Now available in five sizes.




Race Line: Built for the competitive athlete. Our Race Line focuses on Ultra & Trail running but can be used in any running scenario. Our Race Line products are sized to fit the athletic body, feature UltrAcool technology for maxiumum breathability on all race vests, made with very lightweight material for comfort during long distances, and created for pure performance.

  • 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 Sternum™ 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):  2X Small (26″-32″) X Small (28″-34″) Small (30″-36″), Medium (32″-38″) or Large (34″-42″)
Color:  Pitch Black, Emerald Blue*
Hydration (included):  2L Reservoir with mag-clip to secure hose.
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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2 reviews for Zygos 4.0 Hydration Pack (New!)

  1. Rated 5 out of 5

    Jake Grossbauer

    Took the Zygos 4.0 on a test run and after first thought i am happy with purchase.
    Bought it for future all day or even overnight fastpack runs hoping the storage would be enough.
    For grins i tested the underarm pockets which i was able to easily fit multiple gels, waffles, and other nutrions in. The added front pockets allow for easy access to phone pr map while still having bottles in each as well.
    The fit is true to size amd the honeycomb wicked perfectly as it was warm bit the pack did not absorb any.

    The underside zipper pocket on pack was easily accessible and perfect storage for when it warmed up to put buff and gloves in, while never breaking stride

  2. Rated 5 out of 5

    Matt Ozanic (verified owner)

    This vest is AMAZING!! I’ve had many vests over the years but this one beats them all, hands down. I love the placement of pockets, materials used and the overall thought of design that will be long lasting and comfortable at the same time. It is the fine-wine of hydration packs. This pack is going to be great at keeping my fluids cool on my training runs in western Colorado and it will carry all of my needed gear on High Lonesome 100 and The Bear this year. Thank you for all that you put into this pack. It is absolutely perfect!!

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