20oz Soft Flask w/Bite Top, Running Water Bottle, Collapsible Water Bottle, Travel

This is a repurchase as I had to toss my last one during a marathon rather than carry it to the end. I wasn't using my hydration vest, which I do use in training and this flask works great in, especially if you add the long bite tops. In any event, there is absolutely no odd taste or odor from this material and the top does not leak. Also, with the wide top it is easy to refill in a long race at an aid station if you want to. Easy to clean as wel.

Perfect for my need

I actually haven’t tried it yet but I do like the support on one side so you could either carry or put it in your vest pocket.

Works great - the spine piece makes it a lot easier to stow and handle than the typical soft flask. Just enough hydration for shorter runs. It fits great in the stretch pocket of an Endorphin running belt.

A new must have for my backpacking gear. I use a CamelBak for my water but wanted something I could add electrolytes to and this is perfect. I don't go fully ultralight, but pretty light weight. This collapsible flask is perfect for a light weight water bottle that compacts down to almost nothing when it's empty. I've had it on 2 easy backpacking trips already totalling 10 nights. 2 more trips coming up to finish off the summer. Does not leak. No bad taste even the first time using it. So far it seems very durable and I'm sure I'll replace it if it ever wears out. Highly recommend.

Love this bottle for my longer runs. It’s portable and light weight. There’s a thin rectangular plastic backbone that gives the bottle structure. I’ve night cheap silicone bottles and they get flimsy as you drink water and hard to hold. This design is actually pretty genius. I carry my bottle on runs in my run belt and it’s comfortable. I don’t have any issues with smell or taste. The valve works great, even my toddler loves it haha.

I used these in a couple long races. They are quick to fill up at aid stations. They are easy to drink out of the front pockets of my Nathan vest. I relied less on my bladder with these. They were a big help.

Previous versions of the 20oz have an integrated spine to provide support (I have four). The 14oz and 18oz they're selling both have spines (at least the Amazon and Nathan.com photos show spines), only by noticing the absence of a picture of a 20oz with a spine would one imagine it has no spine. The spine is why I overpay for Nathan brand flasks. These bottles are so flimsy and weak that they repeatedly collapsed in on themselves IN the pockets of my Nathan hydration vest. These are of no use to me, that was a waste of $80 (I bought them as spares should my others start to leak - my wife and I both share them).