... .marking materials of metal electric engraving penMachine featureElectric engrave pen is new style elcectrical engraving device.It is easy to ... , chinaware, marble, glass, jade, crystal, plastic,wood etc.. Engraving the words, mark, pattern, the device can turn the button ... by the sub-five, to meet the different materials of engraving. Machine parameterVoltage Range :220V/50HZNib: diameter 3mm(hard ...