This is a 144-LED intensity & direction adjustable ring light with mounting size up to 2-1/2" (64mm) in diameter. The light ring is consisted of 4 individual portions that can be turned on/off separately. You may use the feature to change lighting directions and obtain the best illumination for your application. The ring light has 2-1/2" (64mm) inside and 4" (100mm) outside diameters. It works with power supplies from a 110-220V and comes with a 1-7/8" (48 mm in diameter) ring adapter. With variable intensity control, it provides cool, even, intense and focused shadow-free illumination. It is an ideal durable cool light source for all stereo microscopes, especially for gemological, coin and gem/jewelry microscopes. This kit comes with one year warranty against manufacturing defects. It is brand new in original box. Its retail value is $500.