The Platypus Hyper Flow bite valve is made from a soft, medical-grade silicone that stands up to years of use. It features a fast flow rate & is completely drip free. The Hyper Flow bite valve is compatible with all Platypus hoses & shutoff valves. Soft Medical-grade silicone Drip free Fast flow rate Durable Compatible with all Platypus hoses & shut off valves