Sensor to be mounted on the outside of any tank whose vibrations indicate the inside level.- It can be mounted on tanks of any materials.- It works with any kind of liquid.- Easy to install without drilling the tank (no leaks or bad smell).- 1 to 9 sensors can be installed per tank (each sensor indicates one step).1 single sensor is recommended to report 3/4 black water or water/fuel reserve.Gobius Pro can be programmed via Bluetooth and it can be connected to a warning light, relay or buzzer.It can be read also via Bluetooth (App available for download on your smartphone or other devices).App languages: English, Italian, French, German, Norwegian, Swedish.