This LED illuminator replaces the original Nikon E400 illuminator. It provides a whiter, brighter light than the original, while using far less power. Intensity control is continuous from 0-100%. Don’t replace your microscope because of a bad illuminator. All the original illuminator components are replaced with new parts. This includes the entire power supply, bulb, socket, wiring, lamp housing and intensity control potentiometer. Replace your old E400 microscope light with a new Nanodyne LED system.