Very happy with this purchase - ADE Advanced Optics RD3-006 1x Reflex Green Dot Sight w/Ruger Security 9 Optic Mount Plate

After comparing several optics, I decided to give ADE a try. The package arrived quickly and everything looked professionally machined.

Installation was simple, the controls are intuitive, and the optic has maintained zero through multiple trips to the range. I especially like how low the optic sits on the slide.

For anyone wanting an affordable optic solution for the Ruger Security 9, this is an excellent choice.