This is description of this part:
Carl Zeiss Jena plan compensating microscope eyepieces with 16x magnification
Manufacturer: Carl Zeiss Jena
Model: PK 16x (12)
Magnification: 16x
Field of view number: 12
Mounting diameter: 23.2 mm
Designation: PK = plan compensating - recommended for work with planachromatic objectives, but they also work without any trouble with achromats or apochromats
Because of their very high quality they are often used on microscopes from other manufacturers as well, especially when Carl Zeiss Jena Planachromat objectives are mounted in them. The "compatibility" section lists a long series of microscopes these eyepieces fit - but that list is definitely not complete.
Important: these eyepieces work both on microscopes with a finite tube length (160 mm, for example) and on microscopes with infinity optics. That means you can use them on the Carl Zeiss Jena Amplival microscope just as well as on the Carl Zeiss Jena NU-2 microscope.
A note - eyepieces with such a strong magnification are in my opinion better suited to a quick look than to permanent work. I write "in my opinion" on purpose, because this comes from using them and not from the manufacturer's description.
A 16x eyepiece magnification should be treated as a zoom that brings out no additional detail (the resolution is not increased). This matters for example with heads that have their own extra magnification (such as Carl Zeiss Jena heads with a built-in 1.5x or 1.6x factor) - working with a 100x oil immersion objective you then theoretically get 100*1.5*16 = 2400x, while physics does not allow light from the visible range to be usefully magnified for the human eye beyond roughly 1250x - so this is what is called empty magnification.
What is this part needed for?
- if you don't have these eyepieces in your set
- if you have 16x eyepieces, but they have a smaller field of view
- if you want to replace your poor-quality eyepieces
- if you have Planachromat objectives and want to use plan-compensated eyepieces