TRUGLO Brite-Site Tritium/Fiber Optic Sight, Fits S&W M&P, Green TG-TG131MPT When you need to make a fast and accurate shot" brightness counts. Truglo brought fiber-optics to the shooting sports industry years ago for this very reason. They have now paired fiber optics with tritium night sights to create a consistently bright sight picture-day or night! Truglo's 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.