Stay on Target with XS Sights XS Tritium Night Sights offer the best front sight visibility in all lighting conditions, combining tritium with XS' patent pending glow dot. Upgrade a home-defense shotgun to a high-contrast front sight that absorbs light and glows in less than ideal conditions. Optic Yellow is the best option for low light and has the brightest glow intensity. Primarily based on the white light spectrum, optic yellow is very reflective and will excite the photoluminescent properties of the dot faster than any other color. The increased surface area of the convex dot increases light absorption, intensifying the charge of the glow properties of the dot. Installation requires a drill press to drill the retaining pin hole in sight body. Item Specifications and Features: XS Sights RV-0003N-4G Tritium front sight Ember Glow Dot, Green dot Pin hole must be drilled 10 Year Warranty - No Questions Asked night sight warranty Fits: S&W J-Frame with pinned front and Ruger SP101 with fixed rear