Hydration Bag CAMELBAK BAG Circuit Vest 5 Men's 5L 1.5L GraphiteJapanese
Here's an option that makes it even easier to hydrate than a flask. ・Suitable chest circumference 71 - 127cm. ・Capacity: 3.5L + 1.5L CRUX reservoir included. ・Weight: 160g. Expedited (EMS).