All sets feature a bright red, fiber optic, front sight and fully adjustable peep or U-notch, rear sight. U-notch, rear sight sets use the highly accurate, 3-dot pattern with two green, fiber optic dots at the rear for sharp contrast and quick sight acquisition in all light conditions. No drilling or tapping required for most rifle models. Dovetailed front and rear sights may require minor fitting. High visibility, fast to pickup, sight systems for the RugerA(R) 10/22A(R). 3-Dot has U-notch rear blade with green dots, red front sight. Adjustable for windage and elevation. Mfg: Williams Gun Sight