Aquarium air pump operates automatically when the power goes off! LED battery-powered, the Air Charger II can be set to 2 modes - one for 13 hrs. of constant use, and another for 26 hours of intermittant use. LED battery light display indicates quickly when you're running out of juice. Dual outlets can power several air stones. Also great for quarantine or travel tanks. Charges quickly and easily with a USB cord. 5W of power. Includes pump, tubing, USB cord, and air stone.