Cascade presents the Air Charger I (1 Outlet) by Penn-Plax. While this Air Pump utilizes a USB cord for continuous power for normal use it also features an internal battery that instantly kicks in if power is lost. This keeps your tanks water safely oxygenated in the event of a power outage in your home! Think of it as a 2 for 1! It is both a normal air pump that also gets you out of a pinch! It also features a LED Battery Power Display: 4 lights means fully charged and ready to use up to 13 hours on Constant Air mode or 26 hours on Interval mode.