The Platypus HyFLO Bite Valve is a streamlined, one-piece bite valve that offers fast-flowing, self-sealing, leak-free performance. Made with a soft, taste-free, medical-grade silicone, the HyFLO stands up to years of use. The bite valve is included on all Big Zip EVO & Hoser Reservoirs and is compatible with all legacy Platypus shutoff valves.