Our timeless bite valve helps liquids from escaping so you can keep yourself hydrated no matter how far you go. Your 14oz. Soft Flask with Bite top is perfectly compatible with ALL Nathan hydration vests. Whether you want to carry the flask or slip it into any hydration vests or packs, this 14oz soft flask is the perfect hydration add-on for runs that require a bit more hydration. With the bite top, you can make sure that you have control of where your water or liquids go straight into your mouth and not dripping out the top.