This is the National Optical #910 Mechanical Stage. It fits on many of the high school compound microscopes, such as the 131-CLED student microscope.
This is the MWSTG11 stereo microscope mechanical stage that fits in a 95mm stage plate holder. The glass plate on top allows light to pass through the stage if needed.
Each microscope mechanical stage allows you to move the stage very slowly while looking through the microscope. This ensures that you won't miss any details while scanning specimens. You can view more mechanical stages here.