TRUGLO Brite-Site Tritium/Fiber Optic Sight, Fits Springfield, Green TG-TG131XT When you need to make a fast and accurate shot" brightness counts. We brought fiber-optics to the shooting sports industry years ago for this very reason. We have now paired them with our tritium night sights to create a consistently bright sight picture-day or night! Our 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(R) to provide a bright and reliable sight picture.