Hydro Flask Hydration Pack 10L Hydro Flask introduces its very own, performance-focused Journey Series™ of premium, hands-free hydration. The Hydro Flask 10L Hydration Pack is a compact backpack-style hydration system featuring Cold Flow™ technology designed to maintain cold water temperature for up to 4 hours. This pack is made from a BPA & Toxin-Free, waterproof fabric that is lightweight, puncture, and tear-resistant. Weight: 2 lbs. Built-in cell phone pocket. Includes a magnetic hose clip. HydraPak® Blaster™ Bite Valve. Features a perimeter zipper for easy access.