... 2.12/ 24VDC optional3.Pure sine wave.4.Low frequency, inbuilt transformer.5.AVR function6.Charge current ... discharge protection, over charging protection, short-circuit protection.low voltage, over voltage,over load,over heating protection etc ... DB9, Control panelLCD or LED SelectableAudible alarmAlarm on battery:Low battery & Battery over voltageAlarm on abnormal operation:Over load, Short-circuit, ...