The HD Night Sights were specifically created to address the needs of tactical shooters. The three dot green tritium night sight set?s front sight features a taller blade and an aiming point ringed in photoluminescent paint while the rear sight is outlined in black and features a wider U-shaped notch. This unique configuration increases visibility and quickens front sight acquisition?even in transitional lighting. Additionally, the front surface of the rear sight is steeply hooked to assist in emergency one-handed slide operation. Green tritium lamps are warranted for 12 years from date of manufacture. Fits both the Smith & Wesson SHIELD .40, .45, and 9mm models. Professional installation recommended.