UA045-ZYGOS-BLUE-162114556-WEB_SMALLUA045-ZYGOS-BLACK-162151313-WEB_SMALLUA045-ZYGOS-BLUE-162113624-WEB_SMALLZygos Sizing_15

Zygos (30% off)

5 out of 5 based on 12 customer ratings
(12 customer reviews)

$159.95 $111.97

5.00 out of 5

Have a breezy, easy feeling in the most human compatible vest system ever built.


Product Description

The perfect answer to the multi-purpose adventure pack providing versatility and functionality, easy access to necessities and stable, comfortable reliable performance, even through the most demanding conditions and situations! Suitable for all occasions—from extreme mountain scenarios to biking, skiing, and even, motorcycling.
Includes the new soft touch binding, large capacity quick stash pocket without added weight or bulk, quick attach bladder holder, new elastic mesh on quick stash pockets featuring more stretch, added capacity, less bulk and weight. Soft, large holed, micro-fiber fabric enables excellent circulation, cooling and breathability throughout the vest; and, the amazing trademarked and patent pending Max O2 Sternum™ system is super easy to get in and out of, with or without gloves, even with tired or fatigued fingers. Once adjusted for proper fit, there is no slippage or change in tension. It’s the only system out there that allows for full movement through the chest cavity and unrestricted deep breathing without any loss of stability. Have a breezy, easy feeling in the most human compatible vest system ever built.

• Primary construction of soft, large holed, micro-fiber mesh fabric that makes for lower pack weight and huge cooling and breathability!
• Soft touch perimeter edging with beautiful de-bossed logos for a polished look, and a nonrestrictive feel.
• Patent-pending Max O2 Sternum™: Sternum attachment system with enhanced recoil for better range of motion, quick in and out, boot hook type attachment system, adjust once and lock down to eliminate further fuss even when taking on and off.
• Large capacity main zippered compartment.
• 2 x zippered wrap-around side pockets for easy on the go access.
• 1 internal zippered small pocket for keys, lip balm or other essentials.
• New Bladder hanger system: Lightweight, easy and fast method of attaching bladder inside pack. No struggling to detach or reattach bladder. Great for aid stations and lightning fast refills.
• Adjustable compression straps to hold a fully-outfitted pack stable and secure.
• Lighter weight front pocket mesh fabric.
• “Wrap around” styling for stable fit and comfortable access.
• Includes a 2L bladder.

Additional Information




Clothes Stash, Credit Cards, Gels and Foods, Hydration Ready, Keys, Phone or Personal Device, Pills and Electrolytes, Size

Fluid Capacity

2 L (70 fl. oz) Reservoir

Total Volume

9.21 Liters

Product Dimension (inches) LxWxH

SM/MD: 14.5×1.5×17 LG/XL: 16.25×1.5×19

Weight (Includes Reservoir)

14.4 oz (408 g)

12 reviews for Zygos (30% off)

  1. 5 out of 5

    (verified owner):

    Fit: Fine. It’s snug but comfortable. The straps let you dial in your fit and don’t create pressure points. They are also easy to adjust. I have had it packed with a full reservoir, two full bottles, a vest, hat, and gloves, and there was no bounce. I’m pretty sure it would have been as secure with additional items. I’ve had it out for a few 3 hour runs. I didn’t chafe or have the desire to take it off & toss it like I have with other items.

    Pockets: Like the video says, there is plenty of room for an all day excursion. The back pockets hold plenty and are easy to adjust. I can’t really access the side pockets on the go, but that is probably okay. Being able to do that would mean that my arms would rub the sides the entire time. Even though I mentioned it, it isn’t that big of a deal to me. The front pockets are simple to adjust and hold things securely.

    Valve: I read a review on another site that complained about the valve being difficult to operate. It is if you try to use it in below freezing temperatures, but so is every other valve. In above freezing temperatures it works like a charm. It really does provide a lot of water.

    Other Stuff: Buy the magnet clip. It’s worth the $5.00. I also bought two Ultra Flask 550 bottles. They work great too. They don’t collapse like soft flasks do, but they are super soft. This means they work well in the fly because they are easy to take out of the pockets and put back in. They let out a lot of water. Customer Service is excellent. I told Tina why I wanted a vest, but wasn’t sure which one would be best. She suggested the Zygos and it has worked perfect. I ordered a size too big. It was easy to exchange. Tina sent the return info super quick and they held one in the right size. That was pretty cool since these are on a closeout due to the 2.0.

    The quality of the vest is top notch and so are the people behind it.

  2. 5 out of 5

    (verified owner):

    Breathes with me when hiking.
    Very light. Flexible ways to pack it. For me better than a fannie pack or light back pack for fast hiking. A winner.

  3. 5 out of 5


    Tried a few running vests and I have to say this is the most ergonomic and user friendly one I’ve owned and tried for ultra marathons and peak scrambling. Love the easy to access bladder and accessory pouches, all readily accessible when in need. A+

  4. 5 out of 5


    Looked for a long time after a light running bag with minimum strapping that need to be adjusted every few min of running. I got the Zygos 2 weeks ago and planing to do my next 80K with him.
    Already did 3 long runs over 32K 34K and 36K.
    Bag is nice feels very light, it’s sitting so well on the body you almost forgets it’s their.
    Water pack is very easy to handle and no need for tight lid closing.
    2 things needs to be checked:
    Front mesh pockets opening is too loose and twice I had a gel fell of.
    Lower strap clip is too close to the mesh pocket thus making it a bit difficult catching the strap.
    But other than that it’s great bag!!!


  5. 5 out of 5


    This is my go-to expedition pack or run commute pack. Also for mountain biking too. Used it for my run through Patagonia Chile and had it on for days with no issues. Even stuffed full with gear. Have used it with bladder in back, bottles in the front, easy access pockets. Very versatile.

  6. 5 out of 5


    Weight ??

    • :

      Weight including reservoir is 14.4 oz (408 g).

  7. 5 out of 5

    (verified owner):

    Best hydration system I have used. I have tried a few different packs and this far surpasses all others. Love the easy access to the side pockets, the storage for the mountain runs, and the 2L reservoir is awesome. I love this pack!

  8. 5 out of 5

    (verified owner):

    I wasn’t fan of running with packs until wearing the Zygos. I bought while training for a trail ultra where I needed several hours worth of food and water. The pack is surprisingly light. The sternum straps kept the pack in place while allowing for a range of movement and did not restrict breathing at all. Even at full capacity there was a snug fit and the straps seemed to be wide enough to disperse the weight so it never really felt like running with a pack. The pockets were great for a variety of food, first aid, headlamp, outerwear, and everything else I might need for 6+ hours on the trails. The only minor downside was difficulty gauging water remaining in the bladder (versus running with bottles) and the mouthpiece took some getting used to. I highly recommend the Zygos and have already had a few friends buy this or other UltraSpire packs who are equally impressed.

  9. 5 out of 5


    By far the most stable race vest I’ve used so far! The new Max O2 sternum straps are perfect. The pack itself is so light you barely notice it’s there with plenty of capacity to use on ultras, but i also use it on smaller trail runs as well, due its comfort and lightness.
    I have been using it with the softflasks since i don’t like bladders which i believe gives the pack even better balance.
    Keep up the good work!!!!

  10. 5 out of 5


    The best pack for ultras over the 100km mark! Versatile, light, with LOTS of room for your mandatory gear! Helped me to run my way to a solid 1st place in my first race of the year, the Ultra Trail del Arenal 115 km and will be my partner in RRR 100 and, if I’m lucky enough, UTMB 2016.

  11. 5 out of 5


    I wore the Zygos yesterday on a 50 mile Mountain Bike race. The True Grit is a rugged and grueling race through the Southwest Desert in Southern UT. The Zygos was fantastic! It is the most comfortable pack I have ever worn. I have used several Camelbak packs (including the popular MULE), and the Geigerrig, Rig 1210. While I think both of those packs are great, the Zygos blew them both out of the water. It is incredibly light, and rides very well. It is the most smartly designed pack I have ever used. It has several, easily accessible, well placed compartments to store and grab fuel and gear quickly and easily. There was ample room for everything I needed. The draw-string like closures allow the pack to flex and move with you, while keeping everything in place.

    I don’t know why the mountain biking community doesn’t appear to have taken more notice of these great packs, but I highly recommend the Zygos.

  12. 5 out of 5


    Game Changer! Love the new Max O2 sternum straps! There is plenty of storage when you need it but can compress if you don’t. The side pockets are easy to get in and out of for sure. Love this pack! Can’t hit a long run without it!

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