Featureseye piece eye piece wf 10x/20 with diopter adjustment of botheyepieces & rubber eyecupsworking distance 80 mm regardless of magnificationfocusing range Rack and gear system focusing system. Image sharp andaccurate, Remains clear throughout the whole zoom rangeillumination halogen 6 volt 20 watt & 12 volt 20 wattpower supply switching 220-volt power sourcev 50hzpacked in thermocole boxoptional accessories this ring light is an incident illumination for stereo microscope. Annular fluorescent illumination 110 v or 220 v/8w or 10 wtube typeled adjustable volumedark field for gem observationgem clamp