Oceanic Systems Univ Water Sender 250-500mm 1.25 BSP-3281-T500Oceanic Systems Universal Water Sender 250 500mm 1. 25 BSP 3281 T500 The 3281 Water Level Sender will measure the water level in the fresh water tanks. They provide a 1% accurate tank level to the NMEA2000 marine network. The 3281 can be programmed with up to 100 volumetric points so that it offers the most accurate indication of the VOLUME of water in the tank. This volume information can then be displayed on any NMEA2000 enabled display wherever it