Nikon's 20x metal objective lens MPlan 20x ELWD. I think that there is no problem in practical use of the optical system. There are scratches on the appearance, but there is no problem with installation. The screw mounting diameter is 20 mm. It's quite old and manufactured in the 1990s.
International Buyers - Please Note. The item "Nikon Microscope Objective Lens M Plan 20 0.4 ELWD 210/0 Limited" is in sale since Tuesday, April 20, 2021. This item is in the category "Business & Industrial\Healthcare, Lab & Dental\Medical/Lab Equipment Attachments & Accessories\Microscope Parts & Accessories\Other Microscope Parts & Accessories". The seller is "hiroo-jp2015" and is located in Hyogo.This item can be shipped worldwide.