Nucleus Race Vest

(2 customer reviews)


This item will be released on August 1, 2021.

The Nucleus is a new addition to the vest lineup and features our Ergo X Harness, which is a patented harness system defined by its distinct shape and fit. The Ergo X Harness keeps the weight and pressure points off of the soft tissue areas resulting in better blood flow and cooling. The front pocket is double layered for added capacity. The back compartment is layered with sweat proof fabrics to keep contents safe from moisture and sweat. One side features an on-the-go accessible magnetic pocket for items you wish to keep more secure. The bottom of this compartment has been reinforced with a dual layer of nylon at the stress point for durability. This pack features the UltrAcool Light Mesh for added durability and breathability. The Nucleus utilizes the Max02 Waist closure system which provides an incredible fit with easy adjustment, but also allows for an uninterrupted natural breathing pattern. This vest includes our UltraFlask 550 Hybrid Bottle. One size fits most.

SKU: UA131 Category:



• Silicone and PU coated feather-weight nylon fabrics resist water, abrasion and tears.
• Lightweight, soft, breathable, but strong mesh pulls moisture away from the body to keep skin dry and cool.
• 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.
• Zig zagged stitching over elastic for ultra-durability, increased stretch and rebound.
• Ergo X Harness.

Fit:  Unisex
Size:  Universal (Chest Size:  26″-48″)
Color options:  Ice Blue
Hydration Compatible: 1x UltraFlask 550 Hybrid Bottle 
Reservoir Compatible: Not Compatible
Capacity: 305 c.i. (5L)
Weight: 7.2 oz (204g) with bottle, 4.8 oz (136g) without bottle

Additional information

Weight .45 lbs
Dimensions 4 × 3 × 2 in

2 reviews for Nucleus Race Vest

  1. Nolan

    I’m a big fan of minimalist designs. And when I saw the Nucleus combining the capacity of carrying a lot of stuff with it’s double pocket in the rear (the second pocket is a zippered sweat proof pocket for your phone) and a minimalist footprint using the patented Ergo X Harness, I knew I had to have this one. The main pocket in the rear is made with a 4-way stretch mesh. You can easily stuff that pocket with everything you might need. The front of the Nucleus can carry an UltraFlask 550 with ease in its center pocket. While a little unusual for many of the hydration vests out there, it doesn’t take very long to get used to the central location of the bottle. It may even work well with their Soft Flask with Straw and a mag clip. You can carry additional gels and nutrition in the second pocket up front. I particularly like the clever design in the bottle pocket. It has a vertical split in the pocket to make it easier to grab something at the bottom of the pocket should you decide to use a handheld bottle on your epic run and just store nutrition in the center pocket. It also has two additional pockets up front, one that is sippered and another sweat proof pocket using their magnetic closure system. The feel of the vest is great and it just disappears when you’re running. Using their UltrAcool Light Mesh, it is highly breathable in my humid weather on the east coast. And the max O2 closure system allows for a comfortable and snug fit that moves when you breathe. It doesn’t feel constricting at all! I did find that the shock cords could be just a few inches longer. I wear a large t-shirt and find that the cords are pretty snug even when adjusted all the way out. All in all, it’s a great design for those with minimal needs. It’s really comfortable, breathable and cleverly designed. And I’m pretty sure that I can stuff 3-4 giant burritos in the mesh rear pocket. I haven’t actually tried to eat that many burritos, but it’s nice to know that I could carry them along if needed.

  2. Gary T

    I was a little intrigued by the ergo x harness of the reflective neon vest but wanted more storage (phone & water bottle). When I saw that UltrAspire was coming out with the Nucleus vest I knew I had to try it out. I was fortunate that Jodi Hicks (she’s the best) had one available. I am very impressed. It quick became my go to vest. It is very comfortable and feels well balanced (doesn’t shift & stays secure without being overly tight). It doesn’t get hot and is very breathable even with hard efforts ( raced a 10k in over 90 deg weather). All the pockets are very functional and easily accessible even on the move. The waterproof rear pocket is perfect for phones/wallets. The stretch rear pocket will fit a lot of gear and even an extra 550 flask. As I mentioned you can access stuff in both rear pockets on the fly. The front water bottle is very accessible as well as comfortable. It feels well balanced since it is in the center instead of being on one side (if you are carrying one bottle). I have paired it with 550 handheld ( 2 bottles) which I stored in the rear pocket when empty. I paired it with the Fitted Race Belt as well if needing more water. The zippered front pocket fits several gels. The magnetic pocket is perfect for car keys. It is definitely my favorite vest so far. Thank you Bryce and UltrAspire for always coming out with innovative gear !

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