These adapters convert eyepieces with small eyeguards to larger eyeguards, so DIOPTRX™ can be installed. Note that these eyepieces have shorter eye relief than others recommended for DIOPTRX™. To minimize any vignetting with DIOPTRX™, it's best to use these for deep-sky applications where your eye pupil is large.  When used for bino-viewers, you may encounter "nose relief" limitations because DIOPTRX™ reduces the normal eyepiece eye relief.