... the inverter.Intelligent LED display,contain display of the Utility,Battery,Output,Fault,Saving Mode Power Capacity,Low Votlage,Charging Current ... ControlFrequency50Hz / 60Hz Optional,CPU ControlBattery ManagerAutomatic Manager of Battery Charging,extend the Battery LifeBeepingInverter Mode,Beeping Sound or Slience OptionalEnvironmentalTemerature20oC ~ 45oCHumidity0 ...