AVS protection: grid power input lower &high voltage protection • Ultra-Fast Transfer Relay: Reduce transfer time between bypass and inverter mode, Reduce possibility of voltage drop. • Universal Protection Circuit: Overload, Long life for battery, Earth Fault, Short Circuit, Over-temperature, Soft-start. • Turbo Cooling: Keep the inverter surface cool and higher efficiency. • Germany technology, Made in china. • 100% real power, High surge power, 2 year warranty. • Decide your own AC backup time by choosing different batteries!