Oceanic Systems Univ Water Sender 500-1000mm 1.25 BSP - 3281-T1000Oceanic Systems Universal Water Sender 500 1000mm 1. 25 BSP 3281 T1000 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