TruGlo Bright - Site TFO Handgun Sight The ultimate handgun sight. Uses our patented TFO technology. Unbelievable transition through all light conditions. Glows in the dark. CNC-machined steel construction. Concealed fiber cannot be seen by target. Fits standard holsters. Fits Glock 20, 21, 29, 30, 31, 32 and 37