General-purpose. Eyepieces for planetary observations, fit any kind of telescope.
Varied focal length. Zoom eyepieces that allow changing focal length during observations.
Wide-angle. Wide-angle eyepieces, apparent field of view more than 60°.
Long eye-relief. Provide high magnifications even with short focal length telescopes.
Erecting Prisms and Eyepieces. Invert the field of view so that image is straight through (not mirrored).