Zygos 2.0 Hydration Pack

(11 customer reviews)


The Zygos 2.0 hydration pack is very versatile and Bryce Thatcher’s pack of choice. 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 2.0 comes with a 2L reservoir and a magnetic clip to keep your hands free. Whether you are fast-packing, mountain biking, in a fast race, ultra race, or a summit assault this hydration backpack is the solution for any athlete. Available in three sizes for a more comfortable fit.



 Recommended Use:
50k to 100 mile Ultra trail racing in high mountains or with required gear lists


• 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):  Small (30″-34″), Medium (33″-37″) or Large (36″-42″)
Color:  Luminous Blue/Precipitous 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: 570 c.i. (9.34 L)

Additional information

Weight N/A
Dimensions N/A


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Fluid Capacity

2 L (70 fl. oz) Reservoir

Total Volume

9.34 L

Product Dimension (inches) LxWxH

Weight (Includes Reservoir)

14.0 oz (396 g)


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11 reviews for Zygos 2.0 Hydration Pack

  1. Stephane Guimond (verified owner)

    My “Go” to everything bag!

  2. James Lavin

    I can’t imagine a better race bag. Just used it for Transelkirks and it was far superior to my other packs. One, its very comfortable–the elastic chest straps really work to keep it in place under any conditions and are remarkably confortable. One note of caution, the large is large for trail people–not normal people and don’t think it will work for anyone above 190. The front pockets held the mandatory bear spray and an Ultraspire soft flask without ever chafing or obstructing. The best feature was the underpack loops for tri-fold poles. I pulled them on and put them back in dozens of times without breaking stride. Perfect. And the small pocket under the bag was great for my unfortunately needed blister kit. Pockets everywhere for both phone gps and lots of GU’ss and bars and the waste. And held rain pants, hat, gloves and rain jacket easily in main pack. Hydration also very easy access. Fabulous pack

  3. Chris Talley

    I love my Zygos! It is light and yet carries so much gear. The shock cords make it highly adjustable so it always fits comfortably.

  4. Bruce Grant

    My Zygos 2.0 has proven to be the most comfortable pack I have worn over many years. It fits me very well (size M for a 5’7″/155lb body) , with the load comfortably distributed over the broad harness. Pockets are all within easy reach, compared to the uncomfortable contortions needed for some other packs. Fabrics used in the straps and pockets are breathable, so those areas don’t get too hot and sweaty depending on what is crammed into them. Carrying capacity is quite high, so there is plenty of room for food, clothing and safety gear for 100-milers or long backcountry endeavours, though the pack weight is light enough to use it for shorter distances as well. Bottles are mounted at an optimal position on the lower chest so they don’t bounce or shift, while also leaving room on the shoulder straps for decent-sized pockets that are easy to access. Finally, the pole-mount straps at the back are handy and easy to use without removing the pack.

  5. Richelle Criswell

    I have been running with UltrAspire for the past 5 years. In preparation for a 40 mile trail race with only 2 aid stations, I decided to go with a hydration pack that allows me to carry plenty of water (bladder and two 250mL collapsible bottles) as well as additional nutrition and gear. The Zygos has been the perfect choice. After speaking with customer support (who are always friendly and helpful), I was able to select the correct size and then placed the order. I’ve used it for multiple training runs and have been please with the many options because of all the various pockets (sizes and placement) on the pack. This pack is a great addition to the Astral, Spry, and handheld so that I have the correct hydration gear no matter what distance and terrain.

  6. Mallory

    I have used the Zygos 2.0 for about 9 months. It is a great pack with enough carrying capacity for a full day. Some of the features I really like are the magnetic clip for the hose. I did have to zip tie the part that stays on the pack to keep it from sliding off. The new tab for holding the bladder in place works great and is easy to detach for quick refills. Recently, I carried five liters of fluid (2 liter bladder, two 1/2 liter soft bottles up front, and four bottles 1/2 liter bottles in the pack) for about 6 miles. This was for an all day run with no water refills and I cached 2 liters at mile 6. I was surprised by how well the pack carried when loaded with over 10 lbs. and felt like I would have been ok carrying this much weight all day if I had to. The side pockets are super convenient and hold a lot of food or you can put a cell phone in one side. The elastic front closures are a great feature allowing one to quickly loosen or tighten the pack fit. The pack rides well overall and seems to be very durable with no signs of wear after nine months of heavy use and a few times through the washing machine.

  7. Nici Dunn

    I love the Zygos 2.0 when I go hiking with my dogs. It’s a bit bigger, then the Alpha, which I use for running. I can fit a 3 liter bladder in the Zygos, which is enough water for myself and the pups on shorter hikes. Lots of storage pockets for everything else you need on a hike. Very comfortable!

  8. dj.crites14

    ZYGOS! When asked which pack is my go-to, must have for middle-to-long runs or adventures. Hands down the Zygos 2.0! Since starting trail running back in 2012/13 I have used two other companies for hydration vest needs. Which at the time I did not know any better as far as what to look for. If something went wrong with it I just said, “well part of the territory. After repeat issues I started the long process of looking and after a year of reading and watching video’s from bigger races and keeping note of which hydrations vest certain Elites were using I chose UltrAspire as my next tool to hit the trails with!!! From the get-go the Zygos did not disappoint!! VOLUME, STRETCH, BLADDER, BOTTLES & PLACEMENT hit ever mark for me.
    Volume- I wanted a vest that I could have for training runs with shorter mileage to just get use to race day volume but would fit the bill for 50-100 mile ultras. Like everyone else, after a few runs and rearranging items for better fit I was able to dial in my pack perfectly.
    Stretch- Previous packs for me were very rigid and kept my chest from expanding naturally. And I did not want my pack to bounce due to loosening of the chest closures. So going middle ground was taxing at times. The stretch with the Zygos is amazing for my style allowing me to breathe deeper and relaxed so when I finished a run my shoulder and back muscles were not as tight.
    Bladder- This pack is perfect to allow volume for a bladder and additional gear for longer trek’s. This was a big factor in my choice as well. I wanted to be able to haul as needed but also use a hydration bladder in hotter condition’s if needed. To a degree my be over kill but I have been in races and have ran out or watched someone who ran out of water and for my not fun. (Races with longer distances between aid stations).
    Bottles- The 550 Flasks are absolutely amazing!!! I was not a fan of the soft flasks because I disliked having to fish them out of the bottle of the pockets to refill them. I understand design has come a long way since first issued but I love these bottles. Soft with just enough structure to not collapse. Like in UltrAspire’s video, to help reduce sloshing of water squeeze the bottle to lower empty space/movement of water. This will help with sloshing sound. ::NOTE:: try not to bite the end of the bottle cap. By doing so you will deform the rubber end and when “sealed” it is not sealed. You will bounce water water. Buy a pack of back up caps. Worth the investment in general. (I had the same issue with another brand where the lid cracked and when I went to buy a replacement lid they were discontinued. I had to purchase a waist belt kit to get extra lids.
    Placement- I am 5′ 11″, 180-200 lbs (leg injury earlier this year added some pounds), 42″ chest. The Zygos has put in more mileage then my other two packs have in just the short amount of time I have had it.

  9. John D

    My go to for ultra mountain trail racing and everyday hiking and fast packing. I started with the Zygos 1.0, which I still have as a very capable backup. Best upgrade on the 2.0 is the self-service pole stash capability for those days/races where I want poles sometime and don’t want them other times.

  10. Amy

    After four years, this vest still looks great. I love this vest. It fits like a glove and doesn’t move around when I am running. The vest is designed so I can easily breathe in it. The storage pockets on the sides are easy to open and close while I’m on the move.

  11. Josh Hinojosa

    My go to pack for every adventure. Enough storage to hold anything I’d need but still light and comfortable. Has become my commute bag, holding my clothes for the work day. An essential part of my everyday routine.

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