Irritrol EV-CAB-SEN Rain Master 2 Conductor Flow Sensor for use on a flow – enabled irrigation controller. Once parameters are established, flow sensors automatically detect unscheduled and abnormal flow events that could result from a line break, valve leak or controller malfunction. Should a break or leak occur, the flow sensor(s) will alert the controller to shut down the master valve to prevent further waste and damage. Most controllers will signal via audible alert and message in the display. Compatible 2-way controllers can send remote messages via test (SMS) or email