Glowing bright both day and night TFX sights are always ready. TFX takes their award wining Tritium & Fiber Optic technology even further with all the features customers requested. Fully protected TFO technology encapsulated in a virtually indestructible configuration Impervious to oils, chemicals, cleaning solvents and ultra-sonic cleaning processes Unmatched visibility in all shooting conditions 24 / 7 Utilizes quality Swiss tritium for maximum brightness Glows in the dark No batteries required Concealed fiber can not be seen by target FORTRESS FINISH provides a permanent protective coating for maximum protection Snag resistant design Fits standard holsters Patented