Premium William Optics 2-Inch 99% Dielectric Dura Bright Carbon Fiber Mirror Diagonal for SCT Telescopes - Perfect for Astronomy, Astrophotography & Stargazing Accessories

Though I haven't had a chance to compare it with other 2 inch diagonals, I'm quite satisfied with the optical quality.At least I can tell see the marked increase in contrast and detail compared to the stock 1.25 inch prism.I initially had trouble in SCT adapter parts, and while I tried to attach it firmly into my nexstar evolution 6 OTA, I broke it, perhaps by over tightening it, but the dealer sent me a replacement parts in a week free of charge.