[35mm]

Short Axis: Length of the short side diameter
20mm Short Axis Secondary Mirror 20mm Short Secondary Length, Aluminum Film on Surface, Protective Film, 76mm Reflective Main Use Mirror
Suitable for use with 25mm short axis secondary mirror, 25mm short side, aluminum coating, protective film on surface, and 114mm reflective main mirror.
35mm short axis secondary mirror, short side length 35mm, surface coated with aluminum film and protective film, suitable for use in 127mm, 133mm, 135mm, 150mm, aperture reflective main mirror.
40mm Short Axis Secondary Mirror, 40mm Short Secondary Length, Surface Aluminates and Protective Film Suitable for Use in 127mm, 133mm, 135mm 150mm, diameter reflecting main mirror
Suitable for use with 70mm short axis secondary mirror, 70mm short side, aluminum coating on the surface, protective film and 203mm reflective main mirror