AmScope MSA Graduated Mechanical Stage for Compound Microscopes This graduated mechanical stage attachment is designed for compound microscopes to hold industry standard microscope slides. It has a center mount screw with 2 locating pins at 33 mm apart. Its extended length is 160mm and width 135mm. This graduated mechanical stage attachment is designed for compound microscopes to hold industry standard microscope slides. It has a center mount screw with 2 locating pins at 33 mm apart. Its extended length is 160mm and width 135mm. Two Locating Pins: 33 mm apart Extended Length: 160mm Extended Width: 135 mm