The Centurian with 4X Plug Power is a pre-packaged, permanently installed, automatic generator system that is the first true do-it-yourself standby generator. The system is designed to supply electrical power to a home's essential items and runs off of two common 20lb. LP tanks. An indicator on the automatic changeover regulator signals when the first tank is empty to allow it to be refilled without stopping the generator. Switching to the reserve tank is automatic. When utility power fails, the Power Transfer Monitor signals the generator to produce electrical power to the GFCE outlets. In 30 seconds or less you have the backup power you need. The unit runs on LP gas only, and provides up to 13 hours of run-time.