This is a Unitron 4 inch mount alongside a nearly identical home-built mount of unknown origin. The similarities between them are numerous. They both have the Unitron style declination slow motion controls, large high quality setting circles and are nearly identical in size and overall design. But the home-built mount actually has several improvements over the superb Unitron, including a breathtaking mechanical clock drive adjustment mechanism. The unknown maker of this mount was a genuine craftsman of the highest caliber. I call this mount a Uni-Clone with the greatest possible respect. You can see closeups of the mount, clock drive and corrector on Youtube at http://youtu.be/d1VNP8gpH-I .