The HydraPak SoftFlask 150 mL / 5 oz is conveniently sized and collapses while you drink, helping eliminate sloshing and unnecessary annoyances. The flask can also be easily packed away, or tucked into a pocket, thanks to its lightweight, compact design. The SoftFlask features HydraPak's signature bite valve, which delivers hydration and nutrition rapidly so that no energy is wasted while refueling. To top it off, the HydraPak SoftFlask is spill-proof and self-sealing with a dial that twists to lock, ensuring that there are no unfortunate spills while running.