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This is a Nikon 100X M-Plan Super Long Working Distance (SLWD) objective. Note that this is a 210/0 objective type. It does not work on infinity corrected microscopes.

Magnification: 100X
Numerical aperture: 0.75

Microscope tube lens: 210/0 

The objective is used, but it is in very well conditions. Optics and mechanics are clean as new.