Review on 🏃 Stay Hydrated on the Go: Azarxis TPU Soft Flask Running Collapsible Water Bottles - BPA-Free and Perfect for Running, Hiking, Cycling, and Climbing by Walter Hodzic

I don't know why but it leaked when I had it in my pocket. Not sure why as you have to bite and suck on the lid to get the liquid. As this was my back pocket, it's possible that the fabric became so tight while walking that some of the liquid leaked out. I am not sure. But other than that, it's pretty damn handy. Super easy to wear. When cycling they fit very well in my jersey pockets (no leakage) and don't add much bulk or weight which is very comfortable.