Alpha 4.0 Race Vest

(26 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.



SKU: UA119 Categories: ,


  • 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.



Additional information

Weight N/A
Dimensions N/A

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26 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

  12. Gene Day

    I love the new Alpha 4.0 race vest. I was a previous user of the Alpha 2.0, which I loved. This vest has improved so much since then and the added addition of the zipper to keep the bladder in is great. I do Spartan races and now I don’t worry about the bladder popping out if/when I have to do burpees during the race. I also love the addition of the phone holder. Now, I can carry my phone and still have two bottles up front. I also love the bigger side pouches to store more nutrition. This vest is so versatile and you can carry a little water to a lot of water depending on how long you are adventuring.

  13. Katy Ross

    I love this vest! It is super well balanced and doesn’t rub anywhere even on 5+ hour runs and when fully loaded. The material is breathable and so light. The pockets are well placed to be reachable without taking the vest off. I can even get a light jacket on and off easily without having to take off the vest! My only complaint is size. I am a small woman (like many runners!) and a small is just slightly too big even when tightened all the down. It works but if I had the option I would be happier with an extra small. To be fair, this is the only unisex vest that has ever come close to fitting me and I love it even with the extra room. When it is fully loaded it fits fine, but when it is only lightly packed there is some room. Hey Altraspire, make an extra small!

  14. Morgan Wilkinson (verified owner)

    Fantastic vest! I hardly realize it’s on and everything fits like a glove and gear is easy to access. This is the best running pack I have ever had and look forward to lots of long days in the mountains ahead with this as my new go-to vest. I use a 2 liter bladder and two bottles/flasks in the front on long runs. Easy to store jacket, food/gels, gloves, hat, maps and phone as well. Thanks UltrAspire!

  15. Chris Peck (verified owner)

    This is my 2nd vest, after my bite valve broke on my cheaper Camden Gear vest. On this round of vest-hunting, I did a little more research and tried a few other packs/vests. My main qualities I was looking for were: 1)Fit (I’m a bigger guy) and 2)Rides comfortably with a full bladder on my back. This passes those two tests and seems to have a lot of storage space. Longest run I’ve been on with it was 8 miles, but am sure it will work great for my 26.2 and longer runs!

  16. Connie Durant (verified owner)

    I love this pack! I’m currently using it on a long-distance walk and since I’m on the go for 6-10 hours/day, having easy access to everything I need like sunscreen, food, phone, iPod, sunglasses, etc. is important and this pack allows for that. The cinch-down front pockets safely hold my phone and other valuables and since the fabric is flexible, when I cinch it down all the way, the contents bulge outward, not inward onto my body. The ergonomic design is perfect, too – my arms don’t rub on the sides, and the weight distribution is super comfortable. Thank you UltrAspire!

  17. Jeremy Smith (verified owner)

    I’ve taken this vest on a 27 mile singletrack run and a 16 mile road run. The cut of the vest allows it to wrap nicely around the body without pulling or dragging on any specific area. All the pockets and finishes are well designed and placed. The fabrics perform perfectly for their placement. My main issue is the sizing. I highly recommend you order a size down from what their sizing chart suggests. I am 6′, 165lbs, my chest is 41″. A large should fit me fine, but it’s too big. I’ve cinched the straps all the way down and the bottom one still leaves the vest loose around my abdomen. This results in the reservoir pulling the vest down and ends up bouncing on my waist. If I pull the front of the vest down the fit is perfect, but it quickly shifts back up. I’ll try to rig some way to hold the bottom tighter, but I wish that wasn’t required after paying for a premium product.

  18. Jeff Houser (verified owner)

    I used to run with a cheap hydration backpack that had a reservoir in the back and a single small pocket in the front. That thing had to be cinched up tight to keep from bouncing around and wasn’t really comfortable. I bought the Alpha 4.0 to run a solo marathon and I’m very happy with my purchase. I have taken this vest on training runs as far as 20 miles and have found it to be very comfortable and lightweight. I love all the pockets that allow me to easily carry my phone, one or two 500 mL flasks (in addition to the 2L reservoir), and plenty of gels. This vest doesn’t bounce or slip the way my old one did. I’m very happy with my purchase and only wish I would have bought it sooner!

  19. Jennifer

    This vest has become my go too – especially in the mountains. I can carry all “10 essentials” upwards of 4 L of water if I needed, clothes, food for an entire day etc. I use this for my 100MILE races and my solo mountain adventures. Only thing I wish was different is the top zip pocket could open a little more and I’d love half height mesh pockets on top of the front chest pockets for trash

  20. gregory boytos

    I’ve been running with this vest for a month. it is comfortable, incredibly well balanced, gives a smooth ride while full and i think it looks great too. even empty as a keys/wallet/phone carrier it’s great and the empty pockets sinch down to keep it tight. problems with other packs being too tight are resolved here with the shock cord front closures which keep it tight but let you breathe without feeling restricted. the pass through pocket on the back makes it easy to access items without removing the vest, which is a tremendous convenience. all in all this is my favorite vest so far and i’ve been running with a vest for about 10 years. great piece of gear.

  21. Lori

    The Alpha 4 is a great all around vest for all distances of my training runs. I have used it on a 30 mile run (self-supported), a 15 mile and a shorter 7 mile run. It is versatile so you can pack with everything you need for an all day run with bladder, flask , food and extra clothing for the longer runs. Yet it is still snug and comfortable for a short run with just a flask of water and dog treats.

    I was concerned about the sizing since I have narrow shoulders. The small worked great for me, in the past with other products I have has shoulder straps that feel like they are falling off my shoulders, or they rubbed on my neck. With the Alpha, I do not even notice the shoulder straps because they are so comfortable and fit good on my frame. Plus when packed with very little, I can still cinch down tightly to avoid bounce.

  22. Kate L

    This pack is the only pack I have used that does not chafe my back. I have a whole collection of vests and this one is becoming my go-to for runs of all distances. I love the front pockets and the handy magnetic pocket in the back. I am 5’6 and have broad shoulders and I ordered the small, and I’m glad I did because it is a perfect fit, so they may run a bit large in my opinion, if you are worried about sizing. This pack is full of really thoughtful features. Highly recommend it!!

  23. Sara (verified owner)

    I took my new pack out and I do love the fit. It’s secure and didn’t bounce around at all. I will say it’s warmer than my last pack, I’m hoping that won’t be a problem this summer as it gets very hot here.

    Also as others have stated, the size chart is way off. I have a 36 inch chest which is supposed to be on the boarder of small and medium. On advice of others I sized down and I’m glad I did. The small has tons of room left. Looking at the elastic clasps, there is probably enough room for at least a 40 inch chest.

  24. Wes Faulk

    I’ve tried many vests over the years and the Alpha 4.0 is hands down the best that I’ve ever used. Love the way that it feels like it rides up off your skin, especially in hot/wet conditions. More than enough vest for long unsupported efforts, but light enough to race a 50k in. The pockets are awesome for organization, and you can get to ALL of them without taking the vest off. Lots of excellent features as well, such as the waterproof pill pocket, and the heat reflector in the back to help keep a bladder cool (or prevent sweat from soaking what you’re carrying). For those looking for one vest that does it all, this is the vest for you!

  25. AzMtnMan

    This pack is comfortable and its features are well thought out. Ran nine miles in it today in 85 degree weather. Had a tank top on and much of the pack was on my bare skin. No chaffing or discomfort at all. Fits really close and is the most stable running pack I’ve owned. Carries enough liquids and energy foods for an all day outing. Quality build and full of features that are easy to use and reach. Can’t go wrong with this pack. This is my 4th pack from UltraAspire and have never been disappointed.

  26. Greg M Wilson

    This is my go to vest. It carries a lot of storage, is quite light, and breathable. It’s always balanced and Ive never experienced chafing. There are pockets everywhere, and they expand. I used to run half marathons. This vest has made 20+ mile runs just part of my routine.

    This vest is going to be tough to improve on. The only thing I can think of is if there was some way to clip my Lumen 400z light to it instead of wearing both a vest and a waist light.

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