Generac Automatic Transfer Switches are designed for use with single phase generators that utilize an Evolution or Nexus Controller. This 100 Amp open transition switch is available in single phase with service equipment rated configuration and works in tandem with the generator to monitor the utility power. When utility power is interrupted, the transfer switch automatically transfers power from the utility to the generator. When utility power returns, the transfer switch will return the electrical load from the generator back to utility. Through the use of digital power technology (DPM), these switches have the capability to manage up to 4 individual HVAC (24 VAC controlled) loads with no additional hardware. Generac manufactures the widest range of power products in the marketplace including portable, residential, commercial and industrial generators. At Generac, we protect the things that power your life by providing quality, affordable power solutions. This model replaces model RTSW100A3.