Here is what I believe to be an Olympus Collimation telescope for the centering of illuminator light path and stage top platforms.  it has a focusing eyepiece with calibrated eyepiece reticle. It will fit directly in the light path top opening of an Olympus BX microscope stand. The markings on it are K=50.20, and also a -4 and -1. Optical and mechanical condition are excellent. Thanks for Looking!