The M3784-110 conductivity sensor and probe kit comes with the Madison R2-120 solid state controller and provides do-it-yourself automatic liquid level control. It is easily configured for Two Level Differential, Single Point Protection or Alarm operations, and can be set for Pump-Up (Fill) or Pump-Down (Drain) automatic dual level control. For conductive liquids, the High - Low liquid level can be set by cutting the three included conductivity probes for the proper hights. The conductive liquid is sensed between each probe and ground (common). The controller is also equipped with a sensitivity adjustment to eliminate false actuations in some liquids or foams, and can be adjusted to sense between 1K - 100K Ohms. An easy view on-board LED on the controller indicates the on-off state to output contacts and controller status.