Excellent item. Views as good as regular diagonals. Price very reasonable, a bargain. Highly recommended.
I am well pleased with the item. Good quality!
While most correct-image diagonals are used for daytime terrestrial viewing, I wanted one to facilitate star hopping when using a typical star atlas. I have used this diagonal with 80mm and 102mm refractors that are also equipped with a RACI finder. This diagonal makes star hopping a breeze. Views are crisp and bright with no more chromatic aberration than a typical mirror diagonal. I would have given the diagonal a 5 star rating, but I'm waiting to see how durable it is (the housing is plastic rather than metal).
I've been using the OPT 90º ***** Image Diagonal it looks fine and works great this is a very good product.