Microscopes are a basic piece of laboratory equipment and their magnification enables close and intricate work to be done. The degree of magnification varies depending upon the lens. They are classified according to whether they work with light or electrons. The first group are optical microscopes which work with light refraction; this can be visible light or UV light for fluorescence microscopy. One of the most popular types is the compound which has two lenses for greater magnification. Another is the stereo type which can give a three-dimensional view of a specimen and is especially useful for opaque objects. Electron microscopes work through a beam of electrons striking the object to be studied. The first is the scanning type which has a lower magnification power but three-dimensional viewing, the specimen can be stained with palladium. The reflection type is different because it detects the electrons which have been scattered elastically. Other designs include X-Ray, scanning helium ion, scanning acoustic and scanning probe. Microscopes are found in all laboratories. The compound type is used for examining bacteria, parasites, human/animal cells as well as for drug testing in forensic laboratories. Stereo microscopes are more suitable for microsurgery and watching plant photosynthesis in action.