American Optical Microscopes
americanoptics
Gem Pro microscopes can come with used as well as new heads. American Optical built a microscope head in the 1970 to 1990's that is tough to beat. The AO heads came in several zoom ranges and featured all metal body construction that made them almost indestructable. When we sell these we check the internal gearing and the alignment and if these are ok they are tough to beat.

Pricing with various optics options:
GemPro Microscope Base with American Optical 570 10X-63X $2400