Trijicon H&K USP HD Front Yellow Outline Night Iron Sight Set – HK106Y Fits H&K USP Models 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. NOTE: Professional installation recommended. Dimensions for reference only.