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.