Tele Vue's DIOPTRX 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, so to minimize any vignetting, it's best to use these for deep-sky applications where your eye pupil is large.
This DNA-6000 adapter is intended for use with Tele Vue's Nagler Type-6 eyepieces. When used for bino-viewers, remove DIOPTRX, because limited "nose-relief" and eye-relief will prevent seeing the full 82° field. The new larger eyeguards are still fine for use with binocular viewers.