Get from Amazon : br br AmScope PZK Simple Polarizing Kit for Compound Microscopes Graduated Round Stage 1-18 Lens br br Polarizing kit provides polarization features for compound microscopes br Rectangular base with graduated round stage can be rotated to change the direction from which the light hits the specimen br 516 8mm observation hole for use with standard objectives br Comes with rectangular plate with graduated round stage and a polarizing lens :