This 1.5L capacity water bag will keep you hydrated for up to 2 hours on average. It is compatible with our Zéfal Z Hydro Race backpack and most mountain bike bags. It has a wide opening for easy filling and cleaning. Its silicone nozzle will ensure comfortable and safe hydration throughout your ride. By breathing in after pinching the nozzle, you can precisely control the flow of liquid consumed. The on/off sliding closure prevents leaks during transport. Does not drip when driving, even in the open position.