Front side - M34x0.75 female + M52x0.75 female threads
Rear side - M52x0.75 male thread
Weight - 17 g
This adapter allows using microscope objectives with M34x0.75 mount thread in front of lenses with M52x0.75 filter thread (for macrophotography purposes).
Front side of the adapter has also female M52x0.75 thread to allow you using your usual accessories (like circular light) in this setup.