descriptions the Kinetiksports Hydra Bag Is a Great Accessory for Walking, Trailrunning, a and a Mulitude of Other Outdoor Activites. the Bag Will Fit Almost Any Hydration Compatible Rucksacks and Fits Perfect in Our Shell Backpacks Great for Upgrading Your Back Pack or Replacing an Aging Drinks Bladder. Constructed from Hygenic Material. the Kinetik Hydra Bag Has a Large Screw Cap for Easy Filling and Cleaning , Also a Capacity of 1.5 L the Bite Valve Also Features a Dust Cover to Keep the Valve Clean. – Hydration Bladder – Large Cap – Durable Bite Valve – On/off Flow Valve – Dust Cover