When you need to make a fast and accurate shot, brightness counts. Truffle brought fiber-optics to the shooting sports industry years ago for this very reason. They have now paired them with their Truglo tritium night sights to create a consistently bright sight picture?day or night! Truglo patented combination of Tritium and Fiber-optic technologies unites the best of both worlds. Whether you are in glaring daylight or complete darkness, you can count on TFO to provide a bright and reliable sight picture. Fits Novak LoMount cut .260 Front / .450 Rear (1911 5" Government .45ACP) Ruger SR1911 Models (regardless of barrel length. Novak LoMount cut replacement sights are designed for 1911-style handguns with existing fixed Novak LoMount dovetail cut slides, however some fitting may be required. Installation by a competent gunsmith is recommended. Uses Truglo patented TFO technology The ultimate handgun sight Unbelievable transition through all light conditions Glows in the dark No batteries required CNC-machined steel construction Concealed fiber cannot be seen by target Fits standard holsters Snag-resistant design Please note: Yellow fiber-optics are intended to appear less bright than green to increase contrast between front and rear sights. Novak LoMount cut .260 Front / .450 Rear (1911 5 in. Government .45ACP) Ruger SR1911 Models (regardless of barrel length).