Amphipod Full-Tilt AirStretch Velocity Hydration Waistpack - 20 fl. oz.

Priced: $39.95 Rated:   - 4 stars out of 5 by 22 reviews.
Amphipod Full-Tilt AirStretch Velocity Hydration Waistpack - 20 fl. oz.
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Amphipod Full-Tilt AirStretch Velocity Hydration Waistpack - 20 fl. oz. -

The Amphipod Full-Tilt AirStretchâ„¢ Velocity hydration waistpack offers a lightweight design and a low profile that help eliminate the discomfort of traditional bottle packs.



  • BPA-free 20 fl. oz. Hydraform™ water bottle nests laterally for a naturally comfortable fit


  • AirFlow Mesh™ hybrid mesh technology wicks away moisture and circulates air between your back and the pack


  • The Amphipod Full-Tilt AirStretch Velocity hydration waistpack securely holds its bottle in place and accommodates easy bottle access


  • Adjustable AirStretch belt features ample stretch and chafe-free edging for comfort while maintaining bounce-free performance


  • Back-friendly symmetrical design eliminates uneven weighting, chafing and uncomfortable pressure points
  • Low-profile bottle flattens center of gravity, reducing slosh and bounce
  • 40 cu. in. compartment holds key, ID and cash
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Review RatingNumber of Reviews
Average weight - metric:0.24 kilograms
Dimensions:10 x 5 x 3 inches
Fits waist/hips:21 - 48 inches
Gear capacity (L):0.65 liters
Gear capacity (cu. in.):40 cubic inches
Liquid capacity (L):0.59 liters
Liquid capacity (fl. oz.):20 fluid ounces
Number of exterior pockets:1 main compartment
Pack access:Top
Pack loading:Top
Weight:8.5 ounces
Weight - metric:0.24 kilograms

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Amphipod Full-Tilt AirStretch Velocity Hydration Waistpack - 20 fl. oz. Reviews:

Positive Reviews:

Best in class bottle waist belt

Seldom do I feel compelled to write gear reviews, but in this case I couldn't resist. The Amphipod Full-Tilt AirStretch Velocity Hydration Waistpack is the best I've used, bar none.

I'm 5'6" and 155 lbs. I do almost exclusively trail running, 25-50+ miles per week, and compete in 50K to 50-mile ultramarathons. Until somewhat recently, I would run with a Camelbak hydration pack during ultras and long-distance trail running training. However, refilling the pack slowed my time during aid station transitions (take the pack off, pull out the bladder, have a volunteer refill it, put the bladder away, put the pack back on...). Biomechanically, handhelds have never appealed to me, as they do for many ultra runners. I prefer to keep my hands free, and it makes sense to have the water weight hug the small of your back. Hence I've been drawn to the idea of a bottle waist belt.

After trying several belts that hold a roughly 20oz bottle at a 45-degree angle, including the Nathan Elite and the Ultimate Direction Access Airflow, I was disappointed. They had some bounce, sloshed loudly when partially full, and developed hot spots near the top and bottom where the bottle contacted my back. The Nathan bottle leaked terribly, causing preliminary frostbite on my backside during a run in sub-freezing weather. The UD pack broke before I ever took it out for a single run, causing serious durability concerns.

I'd been eyeballing the Amphipod Full Tilt series. It seemed the horizontal bottle would fit perfectly in the small of my back, as long as the bottle wouldn't leak in that position. In short, I've been extremely impressed.

I adjusted the waist belt so that it fits comfortably, but not overly, snug. The bottle sits in the small of my back, and the waist belt clips in front one to two inches below my navel. The bottle is rock solid. It hasn't budged on trail runs of 10 to 15 miles. No bounce, at all. When partially full the sloshing in the bottle is very quiet and barely noticeable. In addition, the horizontal positioning of the bottle is easier on my shoulder when removing and replacing the bottle, compared to 45-degree holders that require me to reach higher to slide the bottle in and out.

The small bungee that prevents the bottle from slipping out of the holder is easy to operate, even while running. I thought it would be annoying, but after the first run it became surprisingly quick and intuitive to use. My only critique is that the bungee has a small plastic "knob" you can grab to release it off the bottle top. When my fingers are sweaty, or when I have less dexterity because of gloves during cold weather, it can be difficult to grasp. I'll likely retrofit it with a small nylon pull tab that's easier to grab.

The small stretch pocket on the back of the pack easily holds a key, cell phone, and/or gel packs. I find that when the bottle is in the holder, it's more difficult to reach into the zippered opening. Removing the bottle so there's less tension in the pack makes getting into the pocket easier. The pocket fabric did also snag/develop a run from the corner of a gel packet foil. I'm going to add a small zipper pouch to the front of the belt for gels, so they're easier to access, and just stash keys or a phone in the back of the pack where they're out of the way.

The bottle itself is great. Comfortable shape in the hand, snug against the back, easy to squeeze, and the nipple/spout is as high flow as any I've used.

After tweaking my hydration for a while now, I've finally found an incredible setup.
peterbronski at REI on 02/02/2012

Blew away my expectations

This thing is great! I was initially hesitant to buy a hydration belt, but it has been money very well spent. I bought the belt and then immediately went on an eight-mile run to check it out.

One nice thing about Amphipod products is the module design of the belts. It's very easy to pick up extra bottles or pouches in case you need more storage. I was originally looking at getting the four bottle 32oz system, but then I decided to buy the single 20oz bottle belt plus two 10.5oz bottles for a total capacity to 41oz! And it only cost me a couple of dollors more than the 32oz belt. With my setup, I don't have a small storage pouch, but I can add that later if I decided I need one. I positioned the two 10.5oz bottles on either side of the larger bottle, so everything is behind me.

I was worried the belt would bounce around too much when I run, much like a backpack. But to my amazement, it was surprisingly stable. It does bounces around a little bit (worsens when running downhill), but it's very mild and hardly a problem. After the first mile, it wasn't even a distraction anymore.

This thing is also surprisingly comfortable. I'm guessing the stretchy belt helps in that department a lot. After running eight miles, I had no sore spots on my hips or waist, no rash, nothing.

Removing the bottle from the pouch is very easy to do. Just make sure you throw the loop over the top end of the bottle so it doesn't fall out. The pair of 10.5oz bottles that I added also works remarkable well too. They're very easy to grab and even easier to snap back into place.

I did read online some discussion of hand-held bottles vs belts. One of the main faults with the belts is the use of multiple bottles. This apparently makes refilling more difficult and time-consuming, which can be detrimental during a race. Hand-held bottles on the other hand tend to be easier to refill. This was another reason why I went with the 20oz bottle system and then purchased a pair of 10.5oz bottles. All of the Amphipod bottles have decently sized openings, so refills should be relatively fast. Plus, I only have three bottles to refill instead of four.

The large size of the 20oz bottle, plus the fact that it resides inside a sleeve, gives it an advantage of staying cool longer than other bottles. In my case, I put ice into my 20oz bottle so it has the best change to stay cold, and then I drink out of my extra 10.5oz bottles first.
Darth Bling at REI on 07/07/2011

Takes some adjusting, but good pack

I purchased this mainly for the Pike's Peak Marathon. I also have a similarly designed Ultimate Direction hydration waistpack. The UD waistpack rubs a spot along my back waistline, so I thought I would try the Amphipod. I first wore the Amphipod in a 15 mile trailrace and my first impression was that it was difficult to tighten the waistbelt. The elastic belt makes it a little harder to get a snug fit and the the belt clasp isn't as easy to adjust. It took a fair bit of adjusting, but it eventually settled into the right spot. In comparison to the UD waistpack, the other thing I noticed was that the Amphipod doesn't have as much storage room for gels, bars, keys, phone, etc. I don't run with a lot of items, but if I'm on a trail running for 2+ hours, I normally bring along several gels. There is probably just enough room for 3 gels. I didn't have any issues with the bottle leaking. It is easy to remove and put back in the waistpack while running. Since the bottle removes from the right side of the pack, I'm not sure if a left handed runner would find it equally easy to remove? It has a little elastic type cord that slips over the mouthpiece of the bottle which holds it in place and keeps it from falling out of the pack. It might be nice to have one of these on both sides, so then the bottle could go in from the left or the right. Also, I appreciate the extra thought and design to the Amphipod bottle, it fits nicely in my hand. However, I'm not sure that it makes much difference in terms of comfort and how a regular water bottle would sit in a waistpack. All in all, I like the pack and will be using it on more runs. I have a pouch from another running belt that I've been able to slip on and I can keep it in the front with my phone and more gels when needed. The waistpack held up great during Pike's Peak and I did not have any trouble getting it adjusted.
Maryland Runner at REI on 09/09/2013

Comfortable and functional fuel belt

This is my first fuel belt and I hope I will never need another (unless this one is made for years and year to come). After about 3 miles of running, I require a drink and this was the perfect companion to my 5 mile run today. The belt is very adjustable and very comfortable. It is designed for the bottle to sit at the small of your back. The bottle is curved which makes it contoured to both your body and your hand when you pull it out to take a drink. There is a little bungee cord that wraps around the mouthpiece that helps to keep the bottle in place.

Do not let the size of the storage pocket fool you. It is tiny but HIGHLY stretchable. Today I just put my car key inside it but to test it's capacity, I shoved my Droid 3 phone (it's bulky) and a packet of energy chews. I didn't think it would fit but it did.

The bottle is nice because it is not hard plastic. You can squeeze it if you need to take a drink. It's not flimsy plastic either.

I am tall (5'11") with wide hips and this belt fit right about at my waist with extreme comfort. I didn't really notice it was there. I did reach around with my hand a few times to check if the bottle moved at all and it really stayed in place. I was running on city streets and not a trail.

Also, it was easy to reach around back to pull the bottle out for a drink and to replace it without having to move the belt or take it off.
pinkfroggrrl at REI on 11/11/2011

I love it!

First, let me say I tried two other hydration waist packs before this one. I used a Camelbak Delaney Plus and thought it was an instrument of torture. Only made it 1/2 mile before thinking of flinging it into the bushes. Tried another REI pack, same result.

I tried the Amphipod Velocity and I LOVE IT for the following reasons:
1. Once I had the belt adjusted, I barely knew it was there. I wore it just below my belly button, with the bottle nested against my back. I love the elastic belt! (That is what was missing from the other two belts I tried). I had the water bottle and the pocket full.
2. I did not have any issues with the water bottle being secure. It hardly bounced/moved except slightly on a long downhill part of my run and that was minimal. (I ran 11 miles of mountain roads with it, and no problem). The only thing I can say about the other guy who lost the bottle is maybe you didn't put the bungee over the bottle. You reinsert the bottle into the slot and push it slightly into the bungee to secure it. It worked just fine.
3. The pocket appears small, but I fit my cell phone, a package of tissues, and a gel and could have fit more. It stretches like crazy!
4. I love the flat water bottle. Very comfortable!

My only complaint is the water bottle lid. I love the camelbak podium lid. I was able to switch it out...problem solved!

I recommend this pack!
MikeandJen at REI on 05/05/2011

Great running belt

I bought this product to replace a Nathan running belt that I used previously. There were two problems with the Nathan belt that I was trying to solve...1) the pocket on the Nathan belt was just far too small and 2) the water bottle and belt were just bulky.

After reading about a few different belts, I decided to give the Amphipod belt a try. The semi-flat bottle seemed like a plus, and all of the reviews on here were great. After using this belt for the past week, and I can say is that it was money well spent!

First, the pocket on the belt is much larger than my old Nathan belt. I could barely get my driver's license in the Nathan belt, much less my iPhone or anything else. I can get a gel pack or two, my iPhone, and my house key in this pocket no problem. Second, the semi-flat bottle and the overall design is just much better than the Nathan. The belt and bottle curves with your back and the strap is made of a nice material. To top it off, I barely even notice the belt when I'm running.

This belt is everything I was looking for to replace my old Nathan product. Couldn't be happier with it, and I plan on using it for many runs in the future.
mbushnell at REI on 04/04/2012

Great hydration system!

I just received Full-Tilt AirStretch Velocity Hydration Waistpack. Adjusted the belt to my waist, sterilized and filled the bottles (I added other amphipod bottles to the belt for my 10K run), and clipped it on--ran a 5K and a 10K. No problems, no concerns! I always thought that wearing something around my waist would impede my running because of bouncing and riding up or falling down, but the elasticity of the belt supported three full bottles without any movement. The ease of retrieval and replacement of the bottles was incredibly easy and effortless. I actually can relax my arms from carrying a bottle and use my energy to focus on my workout instead of fumbling and passing a bottle. Zippered pouch kept my keys; these didn't even rattle. BTW, I wear a 36-38 inch waist size, but the belt would fit me well, if I were a 40-42 inch waist. The perfect system that provides so many solutions to issues runners face with hydration. My adult son, who is in the military and runs to stay in shape, will get one for Christmas!
clamar at REI on 08/08/2011

Yes, You're Missing Something.

This is a great waistpack. Cinch it up enough and it doesn't move at all -- you will forget it's there. The zippered pocket is just big enough to hold my iPhone and a GelPak. I have done dozens of miles of trail running with this pack, and recommend it without reservation.

The previous reviewer obviously put the bottle in backwards, and/or didn't secure the nozzle with the little strap that keeps the bottle in place. Even the picture on the product listing here hows exactly how this works. And it works perfectly, and is very very easy. Please don't be scared off by a reviewer who either has an agenda, or who did not take ten seconds to understand how the bottle gets secured.

Anyhow, I'm here to buy another of these for my wife for her birthday. She asked for one today after seeing how well it works for me and hearing me rave about it.
More Oxygen Please at REI on 05/05/2011

Finally!! No more bouncing or handhelds!

I have been training for a half and I was getting really frustrated with other packs and just sick of carrying a handheld for miles and miles. This did bounce a slight bit initially but decreased as I drank. The bounce was very slight and not too annoying. Bottle was big enough to keep me hydrated on my 8 mile run and I still had some when I got home. I haven't tried out the pouch but it does seem like enough for a gel, key, maybe a smaller phone. I 'think' you can buy additional pockets that go on the belt if you need more storage. The stretchy belt made all the difference in less bouncing and comfort. I could wear the pack on my lower waist just below my naval, still higher than I would like but much lower than 4 other waist packs I have tried.
HealthyLantern at blogspot at REI on 09/09/2011

Functional and stable

I've used this belt on many runs of 10K and up and it has worked out very well. My only complaint is that the buckles loosen easily so it's important to re-tighten the belt before each run. If the belt is tight enough, with the bottle positioned over the small of my back there is almost no bounce and after the first few runs I was completely comfortable with it. I have had no issues with the bottle falling out, I can only speculate that the reviewers who have had that problem did not secure it with the bungee keeper. I've added Amphipod's pouch for my large cellphone and that works well also.

I give this waist pack only four stars because of the slipping buckle issue, but that's a minor problem and overall this is a very good product.
Tincan at REI on 03/03/2012

Negative Reviews:

For slower runners only

So far I've used this waistpack for running 3 times on hilly trails and once on flat pavement. It is simply not suitable for running at paces faster than 8:00/km or 12:00/mi if your waist is narrower than your hips. In this case, the belt won't stay on the hips, it will move up to your waist while running and it will bounce widely - unless you tighten it enough (very difficult to do while running) but then it will compress your lungs, bowels and everything else in your abdomen. At a pace of 5:00/km it is only comfortable once the bottle is empty, so it might work for you if you start with a continuous steep climb, drink everything up by the time you start the descent, and finish with an empty bottle in your back.

On the positive side, the belt is comfortable once adjusted for walking conditions. The bottle is sufficiently easy to drink from while running, it is very easy to refill and does not leave a bad taste. The belt's stretchy pocket can accommodate a large smartphone (Samsung Galaxy S3 without a case), an ID card and a tissue but not more.

I would not recommend this product for thin people who see themselves more as runners than joggers. It should be very comfortable for short hikes (up to one or two hours, depending on temperature), and might be a good fit for slow jogging or for bulkier body types (not tested). I ended up happier running with the bottle in my hand, so instead I would recommend a handheld hydration set, which lets you carry the same amount of water and personal items.
Martin J at REI on 07/07/2013

Bottle Falls Out

As soon as I opened the product I was wondering how the bottle was going to stay in place. It appears to only be secured on one side with the other side completely open.

I just returned from my first running using it. After the first few miles I thought the product was excellent. The weather is getting warmer, so I really needed some hydration for an extended run. I almost forgot I had the product on. I was also able to put my PDA in the back pocket, thus I was able to drop my arm band which is not very comfortable. Then at about mile 6 I reach back for a drink and the bottle was gone!! I cut my run short and headed home very thirsty! Luckily I was able to find the bottle. However, if I can not figure out how to better secure the bottle this product is going to be useless.

If I am missing something I would like to know, but otherwise at the moment, I wouldn't buy this unless you plan to take easy walks with it.
Jim2 at REI on 04/04/2011

WAY TOO BOUNCY! do not recommend

My friend has a previous incarnation of the amphipod full-tilt waistpack, and he loves it. This new version, though, thanks to AirStretch technology, is WAY, WAY, WAY TOO BOUNCY. I used mine today on a 5-mile trail run and it was torture when the bottle was full. No amount of cinching down the belt on my waist and around my belly fat and super-toned abs helped. I promptly returned it after my run (thanks, REI). Sad--I really wanted to like it, and the elastic pouch seemed to work well.

I highly recommend AGAINST this product if you are doing any sort of running or jogging. (It's probably fine for walking.) The old version, without AirStretch technology (just woven nylon straps), is way less bouncy.
sqroot3 at REI on 08/08/2013

Neutral Reviews:

Workmanship disppointed

I have been running for decades. This is the first hydration device that didn't bump up and down or leak. But the third time I used it the zipper pull sealed my keys inside the zip pocket as it slipped off the track. I should have known this would happen, because I noticed that the stitching was coming unraveled at that far end of the pocket.

I will return the unit for a swap. If the next one fails this way I will give up and add a review.

Otherwise, I would recommend this pack. IF -- and I mean IF - you secure the little bungie around the top of the water bottle, this pack works really well with enough water to get you through an hour run on a room temp day. The pack fits the bottle against the small of your back. The neoprene belt tightens well enough that there is little jiggle. The pocket (the one with the failed zipper) has enough room to hold an iPhone, i.d. and some money.
Sincethe70s at REI on 03/03/2012