... install, high sensitivity, quick response, no false alarm, low power consumption Output a alarm single when there is water length is higher ... .black: DC power cathode3.blue/green: COM port of alarm single4.yellow: alarm single (N.O)If you want to detect little ... water, sensor output alarm single.If need more drive current, an outer drive circuit is needed.HANGZHOU XINJIAN ELECTRINOC CO., LTD. is a ...