Ideal for replacing your old worn-out hydration reservoir the Nathan 1. 5L Replacement Bladder features BPA-free plastic and a large easy-fill opening for quickly refilling water at home and trail pit-stops alike. Its high-flow bite valve keeps you hydrated with minimal effort as you blast down your favorite trail or hike up demanding stretches. Moreover you'll find a quick-release hose for quick cleaning and easy integration with your favorite Nathan hydration pack.