Tech Research Power Transfer Switch 120 Volt 30 Amp This Surge Guard model is a basic automatic transfer switch. It is generator dominant and transfers to generator power automatically when energized after 30 second delay. Once the generator is shut down, shore power activates after a 3 to 4 second delay.Features:Generator Dominant And Transfers To Generator Power Automatically When Energized After 30 Second DelayTime Delay At Power UpProprietary Electrical InterlockDual Contactor ArrangementLimited 90 Day Warranty Type: Automatic Function: Transfer Power Between Shore And RV Generator Voltage: 120 Volt Ampere Rating: 30 Amp Terminal Type: Screw Length (IN): 5.58 Inch Width (IN): 3.31 Inch Height (IN): 7.62 Inch Color: Black Mounting Type: Wall