Nikon Object Marker Microscope Objective

Nikon Object Marker Microscope Objective
Handy little gadget for marking a small ring on the surface of a microscope slide - see the small red ring in the picture.
Appears to have (or have had) red ink in it. Still marks a paper towel but would probably benefit from a wash through and some new ink.
Used but great condition.
I am having a clear out of old microscopic / microscopical equipment from a variety of manufacturers (Leica, Leitz, Nikon, Zeiss) and have many more objectives to sell over the coming weeks so please come back and check out my other auctions.