AmScope 144 LED Lighting-Direction-Adjustable Microscope Ring Light with Adapter for Stereo Microscopes Microscope Ring light with 144 bright white LED bulbs provides strong shadow free illumination Four (4) individual on/off lighting zones for changing lighting directions and obtaining the best stereo images Control box for turning on/off the individual lighting zones and controlling light intensity Mounting size: up to 2-1/2" (64mm) in diameter (inner diameter of the ring light: 2-1/2" (64mm) inside; outside diameter: 4" (100mm)) Wide band voltage power supplies from 100V to 240V