The Sensor Float® mercury-activated, narrow-angle control switch is designed to accurately monitor liquid levels and activate control pump control panels and alarms in non-potable water applications or sewage applications. This control switch is not sensitive to rotation and is suitable for use with intrinsically safe circuits. For the normally open model the control switch turns on (closes) when the switch tips slightly above horizontal signaling a high level, and turns off (opens) when the switch drops slightly below horizontal.