Alpha 4.0 Race Vest

(11 customer reviews)


The award-winning Alpha series is the pinnacle of design, functionality, and comfort. Now entering its fourth iteration, this pack has had unprecedented amounts of care and attention placed into every square inch. The new larger front pockets which feature a drawstring are perfect for holding any of our bottles. In addition, the Alpha 4.0 can also hold a 2L reservoir in its bladder compartment. The Alpha 4.0 features an insulated layer piece that can help keep your gear dry while it’s in the pack, cool you off, keep your fluids cool or warm, or you can remove the insulated layer all together. For durability, this pack comes with reinforced bottom double layer 30D fabrics. Easily access any essentials on the go with large passage pocket or zippered side pockets. Keep your phone safe in the front pocket with the securing strap. Available in three sizes for a more comfortable fit.



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  • Rapid access pockets
  • Magnetic clasps
  • Large zipper pulls
  • Dual sided removable insulated reservoir compartment
  • Extra soft no chafe binding
  • Secure drawstring pocket
  • Large & flat front pockets
  • Easy access passage pocket
  • Double layered 30D fabric reinforcement at the stress points
  • Trekking pole attachments

Weight: 10 oz (283g)

Colors: Blue/Lime

Sizing Range: Sm, Md, Lg

Volume: 366 c.i. (6L)


ErgoFit: The human body is complex with intricate detail and function. The same attention to detail is present in the design of our packs to enable precise movement, contact, and weight distribution which ensures that there is never any inhibition to the biomechanics of the human body.

  • Shoulder straps: Human shoulders aren’t straight, so a pack’s shoulder straps shouldn’t be either. Longer straps allow the back portion to sit deeper on the neck to prevent any rubbing. This addition in length helps to create slope as the straps come over the top of the shoulders and around the neck following the natural curve of the body. The harness then follows an S curve around the arms and chest area to avoid any hindrance to the running motion.
  • Weight Distribution: The harness construction also helps to keep the pack balanced at any capacity to ensure the same high quality fit empty or fully loaded. In regards to balance, the load is positioned lower on the back closer to the body’s center of gravity, the hips. This placement helps to stop unnecessary energy expenditure during the long haul.

Ultracool System: When the human body exerts force, 80% of the power it generates is converted to thermal energy. This means that most of the energy you use when running, climbing, or doing anything else is lost and becomes heat. The hotter you are, the worse you perform. The Ultracool System is a collection of technologies designed to dissipate heat and keep you cool. This system allows you to maintain a lower body temperature by dispersing heat during intense activity, keeping you performing at the highest level.

  • Small Footprint: Anatomically engineered, the pack covers only what is necessary on the body to keep it secure thus allowing for your temperature to remain cooler during heavy energy exertion.
  • Ultracool Mesh: The most breathable mesh on the market, this 3-layered, large holed honeycomb mesh is made from polyester which helps to draw moisture away from the skin without absorption.
  • Insulated Bladder Compartment: Made of Mylar, the insulated compartment reflects and traps temperatures to help keep fluids hot or cold. Additional foam with air pockets creates more space for the insulation to take effect.
  • Max02™ Sternum: The Max02™ Sternum is a shock cord securing system that helps create a comfortable & natural breathing pattern while at the same time keeping the pack secure. The shock cord allows for stretch outward and 100% rebound which keeps the pack snug against your body empty or fully loaded with no restriction of movement.



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11 reviews for Alpha 4.0 Race Vest

  1. Richelle C.

    This is my new favorite vest. I train in a hot and humid environment and the ultra cool mesh material allow maximum breathability. I use a 2L reservoir for water. I like that I have options with the various pockets and pouches which allow me to carry a flask for liquid nutrition, gels/real food, and even my cell phone (iphone 8). I even use the small pouch on the chest for chapstick so I can easily access it while running. The outside pocket on the back of the pack has been a great spot for my lightweight rain jacket as well as my waist lamp for when my runs start or finish in the dark.

    I use the pack for both short runs (10K and shorter) and longer (up to 50K). The footprint is minimal enough that even when it’s full, it still fits like a glove and doesn’t bounce.

  2. Shawna

    The colour, the feel and the fit are amazing. This pack is great for holding all your gear needed for shorter runs/races

  3. Chris Talley

    I hadn’t intended on upgrading from my Alpha 3, but I accidentally tore it and needed to replace it. It turned out to be a blessing in disguise. I LOVE the Alpha 4. I wore it during Western States this year and it turned out to be the perfect vest for the job. The pockets on the side are much more accessible than the previous version. The fit is amazing and it is so breathable that you hardly notice you’re wearing a vest. I also love the versatility of being able to carry bottles and/or a bladder.

  4. LaChelle Drollman

    I love all the pockets, the fact that it can hold and 2 liter bladder, and that it is lightweight. I wore it for a 16+ mile run last weekend and holy back chafing! I have never chafed so much in my life. I’m going to give it another go this weekend. I wore it walking around town with no problem so if I chafe again with running I will at least be able to use it for leisurely activities.

  5. Robert Lancaster

    Wow! All i can say is UltrAspire nailed this one. I’ve used this vest on a few long runs and a few shorter runs and its perfect in every way. First the fit is the best i’ve had on any vest and i’ve tried many. Zero bounce while fully loaded, fits like a glove with no chafing. The first vest i’ve used with a large bladder and really forgot it was in the pack. The side pockets are very easy to open and grab a gel they positioned them perfectly. Plenty of storage for longer races this will be my vest for my next 100.

  6. Ken (verified owner)

    This is a great vest for the long ones – so much smart storage and carries plenty of hydration. I have had the Spry for over a year and always liked the breath-ability and fit of the UltraSpire. Aside from a 2L reservoir, I use one handheld and one 500ml soft flask in front pocket, too. Definitely watch the video.

  7. Beth Ann M.

    Great vest for all activities. I wear it for short runs, long runs, mountain biking, road biking, stand up paddle boarding. The pockets are easily accessible, the silver shield in the pack keeps my 2L hydration bladder cold. Best fit I have found for my shorter stature. The vest doesn’t bounce and I barely notice that I’m wearing it.

  8. Jeff Porter

    I will start out by saying I’ve always been a minimalist vest runner (I love their Spry), but I thought I’d try the Alpha 4.0 for longer training runs and longer Ultras. I was a bit nervous on how I would like having, a 2 liter bladder with gear (jacket, chapstick, phone, food, etc) in my pack. BUT WOW, I can’t believe how comfortable this vest is. It does not bounce, the ergo fit design causes it to just suck to your body to feel secure without being restrictive.

    The side pockets are very easy to access, and it’s a little thing, but I love the design on the vest to hold the bladder straw in place so it doesn’t bounce around, which also makes it very easy to drink on the run.

    The key to a running vest is to hardly know you are wearing one and this one definitely fits the bill.

  9. Erika Zazzara

    I love everything about this vest. I am extremely excited that the soft straw flasks stay in place the whole time compared to other brands I have had in the past. It’s a great vest for racing 50k, 50 milers. Lots of room for nutrition and your cell phone. I recommend this vest to any recreational athlete to the elite.

  10. Ellener Peavyhouse

    This vest has very quickly become my favorite yet over the past several weeks since I began running with it! Zero chafing! All past vests I’ve used have tended to chafe the center of my back because of how much movement they have in the. With the bungee cinching system, the pack stays in place with zero movement! It doesn’t get any better than that. The ergo shape has also been a life saver for me. After having a bicep reattachment surgery just a few months ago with a resulting dissection of my pectoral muscle, other packs pinched the surgical site–not with this pack! I don’t even notice the pack on my shoulders and I have 100% free movement of my arms. Love it!

  11. Darren

    I’m really impressed with the fit and feel of the vest and the little details that went into the design. I’ve worn a couple of other vests from other brands and the alpha definitely stands out for its lightness and design details and versatility. Having the option to carry a bladder, soft flasks and ultrafłasks is a unique advantage

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