More aperture for astrophotography and vistual: provide good image with high contrast; ED glass means visible colour aberrations are reduced to minimum with sharp image; all lens surfaces have been provided with multi coated to reduce reflections;
For astrophotography; sometimes more focal length is required in order for them to be seen at a reasonable size in the image especially for compact objects; there is also no shadowing apparent on small image format camera chips for big plus;
Larger diameter has more scope for lenses: 2 inch diameter allows to insert 2 inch eyepieces into this barlow with double magnification; the large lens diameter also means you will notice no shadowing in the image;
ED Element High-contrast Optics: The first time you observe an object through one of these eyepieces; you will almost certainly be struck by the brilliance clarity and depth of colour in the image
Long Eye Relief Comfortable Observing: The very generous 20 mm of eye relief means your observing is always completely comfortable for all the focal lengths available in this eyepiece series