HydraPak UltraFlask Speed (500ml or 600ml) - Collapsible Soft Flask Water Bottle for Hydration Vests and Running Packs with Easy Open Cap

bought these to have extra bottles and longer stems to drink from. love how they collapse as you drink them. keeps the water slosh down to a minimum. easy to clean and use. would recommend

I am an ultra runner and have just started adding these soft flasks to my packs for longer runs to hold electrolytes or other liquid fuel so I can keep my water bladder with just water. I like how they collapse with use so you are left with a lightweight small footprint of a product. Super easy to refill with the hinged lid (SO much better than trying to fill a smaller spout area). I love that the mouthpieces are interchangeable. I really like the straw but my current running vest sits too high to use the straws and they keep bouncing into my jaw or side of my face, so I am just using the mouthpiece. They are easy to clean, have no odor or taste, and made of quality material. I highly recommend over others on the market

Purchased these for use in a 40 mile trail ultra. I had no leaks and no issue during the entire event. I put them in my Salomon adv skin 12, they were a little tight fit just fine. I was able to bend the straw and use the retention straps on the skin 12 vest. If you do use them in a vest I found I the straws flapped if I didnt make sure the slightly firm oval tops of the bottles weren't all the way down in my vest. As soon as I made sure to push them down so the firm top was below the elastic, they held firm and weren't hitting me in the face. I found that screwing the tops off and on to not be as smooth as the flasks that came with my vest but I only unscrewed them when cleaning them so this really isn't a complaint just an FYI. The pop top enclosures worked great for refueling during my race and gave me zero issues. I opted to go with the 600ml and I'm happy I did as it fits my vest without issue and provides 200ml extra between the two.

These soft flasks have become my goto hydration setup for long distance trail running. I love the size, the ability to pop the bottle open without unscrewing the top, and the bite valve. I think they are the best hydration option I've used. But they aren't 100% perfect. The bite valves seem to hold onto liquid, so you really need to pull the entire hard plastic piece out of the bite valve to wash it. Otherwise, even after a thorough cleaning, you'll still have just a bit of liquid hydration stuck in there. Even that is not too bad, but the hard plastic piece doesn't really nest into the bite valve when you put it back in. I'm always worried that will result in leaking. Along the same lines, some of the Hydrapak bite values lock into place, and some doesn't. (I don't use the extenders; they are too tall for me.) This one does not. So one time out on the trail, as I was drinking, the entire valve popped off, wasting a decent amount of liquid and getting my shorts wet. Not ideal, and it could actually be dangerous to lose liquid in certain situations. But if you keep that possibility in mind, the valve does stay on pretty much all the time. It's not a failure by any means. I'm glad Hydrapak are taking the low hanging fruit for hydration flasks. I just hope they make a couple of other changes to make it a perfect bottle.

I’ve used the bottles on all of my long distance runs with no problem, including my ultras, 50k, 50miles, 100miles with no issues! Easy to clean dry & use on the go!

I use this for outdoor activity, where a full sized Camelbak would be inconvenient. I shoved this into a fanny pack recently during skiing. I noticed that the fanny pack got a little wet inside. I don't know if the bottle weeps through the cap, or through the drink nozzle. The plastic taste went away after rinsing a couple of times with plain water. I have also learned not to fill this completely to the brim, as closing the lid will always lead to some of that liquid spilling out.

Performed as expected. The product did not leak - easy to carry - it is collapsible - dries without issue - Con: slight plastic taste to water.

The soft valve is made to be interchangeable with the straw. Which might seem like a feature at first, but it means that it's very tenuously attached to the cap. I went to take my first sip from it at mile 18 and the cap just came right off, causing my fuel to start spilling EVERYWHERE. By the time I was able to fix it, I'd lost almost the entirely bottle onto me, which was pretty unfortunate. Do not recommend.