This is description of this part:
Top lens of the Zeiss CPL W 10x/18 microscope eyepiece
Most important: this is not a complete microscope eyepiece. This is a service part - a component for repairing the eyepiece.
Lens position: this is the topmost lens of the microscope eyepiece, called the eye lens
Lens construction: this is a cemented lens, flat on one side and convex on the other
Matching eyepiece: this is the lens from the Zeiss West Germany CPL W 10x/18 eyepiece, model number 464022-9901
This lens is not a replacement part for the microscope. It is a part for repairing a microscope eyepiece - and that eyepiece can be used in various microscopes, even from manufacturers other than Carl Zeiss. A few microscopes this eyepiece can be used with are listed in the "compatibility" section, but this is definitely not a complete list. It is safe to assume that the Zeiss CPL W 10x/18 eyepiece can be used with any microscope from any manufacturer whose head has a 23.2 mm eyepiece tube diameter.
What is this part needed for?
- if the top lens of the Carl Zeiss CPL W 10x/18 eyepiece is damaged, for example scratched, cracked or chipped
- if the cement between the two parts of this lens (because it is a cemented lens) has discoloured or the two lens elements have started to separate
