OLYMPUS MC-04 MICROSCOPE 35MM CAMERA ADAPTER

Lens and connector in good condition. With minor signs of prior use. All functions are smooth. The lens is in perfect condition as well. No scratches, no cleaning marks, no haze or other anomalies. I think it is a connection/adapter for Olympus OM camera to Olympus microscopes, but I’m not sure what it true function is.  Screw thread has a 25mm diameter, at the rear it is 40mm wide.