Focus os via a fine-pitch screw mechanism. The knob at the top turns the thread, which raises of lowers the microscope cantilever.
The stage is brass with two stage clips and a hole for the Bull's Eye lens support
The substage mirror is supported by a lever mechanism that allows several degrees of movement. The mirror has two reflective surfaces: flat and parabolic.
Mounted below the stage on a swing arm is a five position aperture wheel.