Yoyorule 2L Water Bladder Bag Backpack Hydration Pack Hiking Camping Material: Nylon. Size: 42cm x 25cm/16.54"x9.84"(L x W) Constructed by high quality Nylon fabric, lightweight and durable. With inner pocket. Easy to use on/off valve on the hydration bladder. Storage compartment for keys, phone, snacks etc. Multifunction Backpack bag. Adjustable chest and shoulder straps. Suitable for outdoor activities like cycling, rock-climbing and hiking.