The Dip-Pipe Level Sensor is ideal for usage in fuel tanks. Its 38 mm diameter vertical tube contains a float inside, which measures a level of the liquid. Small holes at the top and bottom of the tube act as a baffle to fuel sloshing around in the fuel tank, so the float position remains stable at any sea state. Sensors are made in various lengths starting at 150 mm increasing to 1200 mm - please ensure that the length chosen is at least 4 mm from the base of the fuel tank once fitted