The CAMP Hydrobag is, as the name suggests, simply a bag for water. It's also simple to use with a wide cap for filling and a drip free drinking tube. There are convenient holes at the top for use in attaching to the inside of CAMP backpacks, which helps keep the bag upright and the water flowing down through the tube connection at the bottom. The bag is puncture resistant, free of harmful chemicals, and holds 2 liters of refreshing H2O.