this is a support for a USB microscope with gear to set the view as well as you want.just adjust the axe and tooth of the gear and toothed-rack. insert the U piece in the toothed-rack, then insert the Wheel in the U align as well the center of the axe hole. then enter the axe kindly forcing, then the piece called molette on each side of the U. finishing by insert the toothed-rack on the base. you can put a drop of glue in the hole of the base. then screw the piece that hold the microscope on the U piece (not included in the STL files)