These images illustrate the fine focusing mechanism of Grunow's No. 5 (First Class) microscope. The stage, attached to the limb by four screws, has been removed for clarity. The fine focus knob, when rotated clockwise, drives the long lever downward, pushing up on the dovetail-shaped fitting. The dovetail-staped fitting is held downward by a very strong spring, preventing any backlash.