Objective MPLN20X-1-7, M Plan, Achro, incident/transmitted light, 20x/0.4 wd 1.3mm

This refers to the magnification factor of a single microscope lens. A lens with the number 40 is referred to as a scale of 1:40 or simply a factor of 40 times. If you multiply the lens factor by the eyepiece factor, you get the magnification.

The light source illuminates the object and is available in various forms.

The object can be illuminated from above as well as from below.