This is description of this part:
Top cover of the phase contrast microscope condenser Carl Zeiss Jena Phv Apl 0.9.
This service part (repair element / replacement part) most likely also fits other turret condensers made by Carl Zeiss Jena, because in the vast majority of cases different models differ only in the mounting and optics - the internal mechanics and construction are otherwise the same.
In the photo gallery detailed photos of this element together with the dimensions are available. Additionally, in the last photo an arrow indicates which element it is and where it is located in the condenser in order to clearly identify this part.
What is this part needed for?
- as a service part in the form of replacing the entire element if it is damaged or heavily worn in the condenser you own