If you are looking for a lightweight space-saving water bottle then the Hydraulics Soft Flask from Osprey is the perfect choice. It comes with a choice of caps; a standard sports cap for best use post sport, but also a bite valve with extension hose options that's ideal for use on the go.
The soft flask is an ever popular choice with trail and ultra-runners as it can be easily stowed, squeezed, and then rolled up and stuffed into a pocket without a faff. Simply place within a shoulder strap pocket for easy access, which makes refilling easy compared to removing a reservoir from your pack.
You may also like....