Introducing the Big Zip(TM) EVO-the latest evolution in taste-free hydration. The Big Zip EVO delivers a significantly higher flow rate than previous Platypus reservoirs and a host of new features, making it a great option for backpackers, hikers, and mountain bikers. Secure SlideLock(TM): Slides both directions to easily open, securely close and fill reservoir. Handy Pincher Grip: Allows for easy one-handed filling. High Mount Quick-disconnect: Offers fast, easy access-no more digging down in your pack. Leak-proof Shut-off Valve: Instantly stops flow and offers reliable stowing. Semi-rigid Center Baffle: Offers low-profile support and makes for easy cleaning and drying. HyFLO(TM) Self-sealing Bite Valve: Improves flow along with new, larger 5/16" drink tube. Funk-free: Embedded Silver-ion protects clean water from mold & bacteria. Pure Platy Experience: All materials are certified taste-free, BPA-free, BPS-free, and phthalate-free.