of fiber optic cables 24a and 42b pass through the outer housing surface into the housing in a sealed relationship with the housing a donut shaped float 104 with a centeral permanent magnet 106 is positioned around the housing 96 whereby the magnetic influence of permanent magnet 106 and the magnetic influence of permanent magnet 100 interact the diameter of the center aperture 108 of permanent magnet 106 is just slightly larger than the diameter of the housing 96 in operation the level measuring device is fixedly positioned in a column of fluid 110 and sufficiently emerged therein to measure a range of fluid surface elevations the elevation of fluid 110 establishes the vertical location of the float 104 and magnet 106 relative to the top and bottom of the housing the permanent 100 and 106 having different adjacent magnet poles causes the magnet 100 to establish a position adjacent to the magnet 106 light transmitted from one of the fiber optic cables 42a or 42b is reflected from the reflective surface 102 of magnet 100 to the other fiber optic cable obviously light reflected in this manner will very in intensity with changes in the vertical position of magnet.