The perfect companion for any walk or run so you can stay cool and hydrated. This large-capacity 18oz. soft flask fits great in front hydration vest pockets, or as an extra in the back storage or stash pocket. 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. The best big-time insulation for a big-time thirst!CLASSIC DESIGN Our timeless bite valve helps liquids from escaping so you can keep yourself hydrated no matter how far you go. SIMPLY COMPATIBLE Your 18oz. Soft Flask with Bite top is perfectly compatible with ALL Nathan hydration vests.