Rack and pinion focusing mechanisms work via a round cog-wheel type gear (the pinion) which engages the rack (teeth). This type of control offers a smooth motion throughout the focusing range.
Adjustable Interpupillary Distance Works by changing the distance between the microscope tube and the pupils of the eyes. These microscopes have a graduated scale to indicate the actual distance between the eyepieces. This allows the viewer to determine the optimum number so it can be quickly set before each use.
Rotatable Head Rotatable head makes it easy for more than one user to examine the same specimen simply by swiveling the head from front to back vertical or in the case of horizontal side to side.
Cordless Illumination allows the microscope illumination be powered with a battery, this means that the microscope does not need to be connected to an external power source.