L3203/L3220/L3230/L3230BD series upright metallurgical microscopes are suitable to observe surfaces of opaque object or transparent object. They are equipped with excellent UIS optical system and modularization function design so that provited excellent optical quilatity and operation performance, update system expediently and provided observation in refelected or transmitted and mixed illumination, polarizing observation, dark field observation. These instruments have beautiful sculpt,convenient control and clear image. They are the ideal instruments in research work in biology, metallography, mineralogy, precision engineering, electronics, etc.