TRU Zip Waterproof Zipper: Durable, leakproof closure for secure hydration on the go Single-Handed Filling: Integrated handle and pinch grip make refills quick and easy Universal Pack Compatibility: Hangs securely in any hydration-compatible backpack Rigid Backplate Design: Maintains shape and simplifies cleaning—no baffle required High-Flow Hydration: Big Bite Valve delivers 20 percent more water per sip with leak control