Built in rechargeable 1200mAh battery. Can used for 30-40 days or around 4-5 gallon water once full charged. The electric pumping device suitable for pure bottled drinking water, suitable for a variety of models gallon barrel without pry the lid. It's easy to use: just press the button on the top of the dispenser. Press once to turn it on and once to turn it off. Once powered on, it will automatically stop working after one minute for protection. Charging by USB cable Suitable for pure bottled drinking water, compatible with most of bottles