Celestron's Erect Image Diagonals are an Amici prism design. This design allows you to look into the telescope at a 45° angle, at images that are oriented properly, meaning the image is upright and correct from left to right.
Reviewed by 3 customers
This product is easy to use, slide it into the scope's visual back, secure the set screws, slide the eyepiece into this and secure the set screws. It could benefit from compression rings instead of screw tip pressure to hold the eyepiece.
Well made, sharp optics.
I purchased these for use in building stereo microscopes It is intended for use on telescopes It appears to me to be a name branded generic item that is imported. It appears to me to be a sturdy, reasonable quality item suitable for telescopes or microscopes that use or will adapt to its eyepiece & tube size