The redesigned version of the Big Zip features a new taste-free drinking tube, high-flow shutoff valve, and face-mounted hose port for superior performance and ease of use. Drinking tube and reservoir are lined with polyethylene to create a completely taste-free system and resist bacterial growth. High-flow shutoff valve is angled at 90 degrees for no-hassle, hands-free hydration. Wide opening and new rounded corners make filling and cleaning easy. No-hassle closure features a self-energizing seal to prevent accidental spills.