Maretron's tank monitor system is used to sense fluid levels of tanks by using ultrasonic technology. Ultrasonic or sound waves are transmitted via the tank monitor system mounted at the top of the tank and the flight times of the sound waves to and from the fluid are measured much like a depth sensor. What this means for you is that there are no difficult to handle long probes protruding into the tank which often foul and/or corrode. Once the tank monitor system calculates and transmits the fluid level over the NMEA 2000® network you can observe tank levels anywhere on the vessel where there is an NMEA 2000® compatible display such as Maretron's N2KView® vessel monitoring system or by Maretron's DSM570 / DSM410 color graphics displays. The tank monitor system is capable of sensing fluid levels in tanks up to 40 Inch (1.02 Meter) in depth. It can be used for diesel fresh water waste water black water and oil tanks. Unlike most tank senders that only work with rectangular tanks the tank monitor system can be calibrated for irregular tank shapes so you can know the true fluid level in your tanks. Tank Monitor System Transmits Liquid Levels Over An NMEA 2000® Interface Integrated Ultrasonic Level Sensor Can Be Used In Tanks Up To 40 Inch Deep SAE J1810 5-Hole 1-1/2 Inch NPT Or 1-1/4 Inch BSP Mounting Accommodates Irregularly Shaped Tanks With 16 Point Calibration