See Level SeeLevel II (TM) LED Tank Monitor System for 3 Tanks 709-P3-1003 20-7078

Used to monitor battery voltage, fresh water tank, gray water tank & black water tank levels. The monitor panel is 2.8 inch wide x 4 inch height. Includes 3-way pump switch, LED display, sender strip & pigtail. Measures up to 3 holding tanks. A single two conductor wire is used to connect all the sender panels to the display.