Zeiss Binos?

Why are the converted microscope heads so cheap? They have them advertised for under $200 with EPs?
I realize that the microscopes don't use the same size splitter, but is it that much different?
Floyd

Floyd,
I think it is more the size of the prisms, the clear aperture in microscope prisms is just not big enough to illuminate all telescope eyepieces. Microscope eyepieces I've had have either been a bit smaller than .965" barrel or a bit smaller than 1.25" and widefield eyepieces for microscopes don't seem to be as wide as what we are used to. Binoviewers for telescopes started to become popular when purpose built binoviewers allowed the use of eyepieces with around 26mm field stop - like 24 Panoptics, 30mm Ultima/Ultrascopics, 24.5mm SWAs etc. I would bet that the microscope heads are 22mm clear aperture or less - I measured one microscope head at 17mm aperture, but I don't know that this is any kind of standard.
Nils