The Stilo Helmet Drinking System Kit is designed for use with Stilo ST4 and ST5 helmets with Drinking System preparation. This kit, which contains all the helmet side of the Drinking System, includes a silicone rubber bite valve with anti-backflow system (YA0601), a water tube (YA0602) and a male quick release coupling (YA0603). Once plumbed into the helmet all pipes are fitted internally.The pipework fits neatly behind the helmets lining so no interior modifications neededEnables you to drink and stay hydrated in a raceThe side port (or front chin pad / vent in the case of the ST5F N) in the helmet allows easy connection to the hydration bags with its quick release connectors.