Nikon SMZ-1/ 1B, 2B, 2T Roataing Diascopic Polarizer/ Analyzer Set.  This set for simple polarization is new but maybe not in  original box and will only fit the Nikon stereo microscopes listed to my knowledge. The analyzer has a thread size of 43.88mm and screws into the bottom of the microscope, it is fully rotatable 360º. The Polarizer fits the 88mm opening in the transmitted light stand, it is also rotatable 360º.  There are four mounting screw holes on the bottom of the polarizer to secure it to the stand.  These kits are extremely hard to find and especially in new condition! Thanks for looking.