Leitz  NPL: Fluotar 100X oil immersion Microscope Objective number 519-847.  It will fit the Leitz Laborlux series of 160mm TL microscopes.  The numerical aperture is (n.a.) 1.32 and it requires a cover slip thickness of 0.17mm.  This objective also works very well with other microscope brands, such as Nikon, Olympus and Zeiss, but only on models with 160mm TL systems.  It will not work with other systems, such as 170mm TL or Infinity TL systems. All glass is free from fungus, dust, scratches, element separation, or oil fouling of internal lenses. The image is very pristine, just like new and especially good in fluorescence.  THE SALE IS FOR ONE EACH