SPECS: 4140 steel, blue, matte finish. Set contains ghost ring rear sight with a tritium dot on each side of ring and front sight with single tritium dot. Rear aperture - .193" (4.9mm) diameter. Glock fits models 17, 19, 22, 23, 26, 27. Plain rear sight without tritium inserts available separately; may be used with factory front sight. Colt Tritium set uses a 65° x .330" x .075" dovetail front sight, installation requires modification to slide.