The Progressive Dynamics PD52DCSV Automatic Power Transfer Relay Switch features a DC coil that eliminates the annoying buzzing during operation. The PD52DCSV incorporates over voltage surge protection of 3300 Joules at 103,000 Amps and two green LED indicators that provide quick and easy indication of generator power or AC power availability. Two separate red LED indicators, when “ON”, display the need for service required for the shore power connection, indicating there has been a destructive power surge! Senses generator power and prevents two power sources from entering the AC distribution panel at the same time. Time delay circuit board ensures generator voltage is at a stable level before transfer occurs. Rugged, heavy duty, screw type wiring terminals are ready to wire the the contactor base. Protects expensive RV electronics from damaging power surges, open neutral and reverse polarity. Easily remove protective cover with wiring schematic inside Dimensions: 10-1/4″ x 8-1/4″ x 5-1/2″ 70 Amp neutral rating. Limited 1 year warranty 240 Volt AC, 50 Amps Floor mount Color: Silver