Nikon Plan 50x Oil Microscope Objective

This Nikon Plan 50x oil objective is designed for use with Nikon scopes that accept M25 threaded objectives such as the E200, E400, E600, E800, 50i, 55i, 80i, 90i, Ci, etc. It  has a N.A. of 0.90 and a working distance of 0.35mm. 

This objective is used, but working like new.