Svbony SV188P 1.25" Dielectric Diagonal - F9171B

The SV188P 1.25" Dielectric Diagonal from Svbony is a very economical upgrade for most smaller telescopes that came with a stock diagonal.  The 1.25" nosepiece slides into the focuser of most refractors or SC telescopes, and if your scope has a 2" focuser, it is easy to use a 2" to 1.25" adapter to use this diagonal.  The other end of the diagonal is also 1.25", and accepts a plethora of universal standard 1.25" eyepieces as well as Barlow lenses or other accessories that have a 1.25" barrel, like photo adapters & more.

When looking through this 90-degree diagonal, you will see images that are upright but left-to-right reversed.  This is not a problem for astronomical viewing, but if you will be using your telescope for terrestrial viewing, you may want to add a correct-image diagonal (right side up and left to right correct) to your accessory box.  

The dielectric coatings on the diagonal mirror provide a a highly reflective (99%) surface so that you lose very little light when doing astronomy.

A brass compression ring is used in the eyepiece side so as to not scratch or mar your eyepiece when you tighten the thumbscrew.  Some lesser diagonals use the thumbscrew itself to tighten against the barrel, and over time, you will see lots of little scratches.  Not a big deal, but if you can keep your eyepiece looking like new, why not?

Finally, this diagonal comes with a barrel insert for one end and a cap for the other, as well as a box, so you can keep the optics clean when not in use.