This is an interchangeable style Ruger MK II and Ruger MK III pistol sight. It includes six fiber optic family LitePipes, in various colors, a carrying case, and a key to interchange the LitePipes. It fits Ruger MK II and Ruger MK III target models with a tapered 6 7/8” barrel, and an adjustable rear sight. Specifications: - Fits: Ruger MK II and Ruger MK III target models with a tapered 6 7/8” barrel, and an adjustable rear sight