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.