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

It’s solid and the best ones on the market. I have zero idea how I can even complain about it but it does exactly as advertised and don’t notice anything wrong with them. Bought them for my outdoor vitals skyline 30 since I lost one due to tsa. But for what it is I love them. I don’t have any leaks, stores flawless in several running vest I own and two different backpacks, it’s easy to carry and no funky taste and they are easy to clean so I don’t mind putting in some tablets in them even if trailrunning a two day trip. Plus I love the straws so it’s right by my face so I don’t even need to reach and drink instead I just turn my head and bite the valve and drink. It’s just all around a good design

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

Bought these to put in my vest for training for a marathon. I love how light weight they are and easy to refill! Awesome that I can put them in the dishwasher and not worry about left over taste from electrolyte tabs. Because they are so flexible, a vacuum is created as you drink from them. So at first when the bottle is full, it can stand on its own. After the first sip, the water stays at the top of the bottle in the mouthpiece and the bottom of the bottle starts to curl upwards and suck into itself and it can no longer stand on its own *unless* you blow air back into the bottle to give it shape again. Completely empty, it lays flat on itself and is quite small. See pictures! Some reviewers were mad about this feature but that is how they were designed- to be slim and lightweight for exercise vests/belts, not for carrying by hand and resting on tables. Looking at buying more in different sizes!

I love these collapsible bottles. I use them in my hydration vest for those runs that are just too long for a waist-band bottle, but too short for a full hydration bladder. I love it that they came with 2 lengths of tubes, but I personally found the longer ones just too short....I had to contort my neck to get to the tube, and when the water level dropped and the bottles collapses (as it should) the tube did not stay in my hydration vest loop thing and then bobbed all over the place which annoys me. I ended up going to a hardware store to buy a longer length of plastic tube to use instead....now it's great. That's the only reason for dropping 1 star.

Good product

I wanted to find easy to use, collapsible bottles that I could put in side pockets for long distance (marathon) running. These worked perfectly for me. I ran a marathon with them - they didn't have a horrid taste (I did wash a couple of times before using), I could fit in my side pockets (running tights), I could take out and put back into my pockets whilst running, I could easily fill at a water station and simply squeezing the top when drinking meant I could suck water regardless of how full the bottles were (no need to hold upside down and no air consumed when sucking the lid). They were completely collapsible when empty (aside from the hard plastic lid) so I could squash completely into my pockets. I will use these for all long distance runs now. They were exactly what I was looking for and hoping for.

They are solid, take a beating, and do the job… I would purchased them again.

I like them. Stand on the bottoms with the lids off which makes aid station refilling much easier.