Check the listing for details. NIKON Fl 70X/1.25 Strain Free Oil Immersion Microscope Objective. Condition: New. Listed at 99.50 USD. Pictured is a very rare Nikon Fluorite 70X Oil Immersion microscope objective, short mount. It is intended to be used on the older black series of Nikon scopes such as the Lk and Su models. The "S" on the case signifies that the glass is strain free making it very suitable for polarized microscopy. If needed it can be parfocalized with and an extension collar allowing it to be used on more modern 160mm Tube Length microscopes. This objective has an n.a. of 1.25. The optical and cosmetic condition are excellent! I have a personal one of these objectives that I have parfocalized on my Nikon microphot, and the images are stunning because the glass is fluorite grade. You will not be disappointed in your purchase, thanks for looking!