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

Go big. The largest of our ultra-light series, the UltraFlask 600 ml holds more so you can go the distance. Its soft material allows it to fit snugly in most vest pockets and it shrinks as you drink t...