The Southwire Surge Guard 40450RVC3 Transfer Switch is a permanent switch for power boxes from Southwire. It automatically transfers to generator power after a 30-second delay and shifts back to shore power after a 3-second delay once the generator is turned off.• Total electrical protection from faulty park power.• Provides protection against power surges, open ground, open neutral, low and high voltage, reverse polarity, and high and low frequency.• Multi-mode surge suppression.• RVC communications allow instant display of voltage, current, and fault conditions on an RVC compatible device.• RVC network communication of both generator and shore power availability through exclusive shore power sensing technology.• Allows the RVC network to better control the power source of the RV and reconnect with shore power when it's available.• Indicator lights on front of ATS indicate presence of input power for L1 and L2.• Voltage and current continuously monitored and indicated.• UL approved 1008 full transfer switch rating and UL/CUL listed. SpecificationsAmps: 50AHertz: 60 HzJoules: 3350UL Approval: UL 1008Voltage: 120V/240VDimensions: 8.84"W x 13.5"L x 5.21"D Shifts back to shore power after 3-second delay once generator is turned off Total electrical protection from faulty park power Multi-mode surge suppression | Southwire 40450RVC3 50A Automatic Transfer Switch