Nikon E400, E600 Fine Focus Gear.
Comes with a set screw to secure it onto the original focus shaft. This gear replaces the original plastic gear that is known to break. Replace it once and be done.
Specifically designed and built just for Nikon microscopes with the correct tooth shape and angle. Meshes perfectly with no vibration.
Will fit Nikon E400, E600, E600FN, ME600 and possibly other scopes.
Nikon E400, E600 Fine Focus Gear