An alternative to traditional sights, Pro I-DOT sights encourage accurate, instinctive sight alignment without taking the time to line up a three-dot sight picture. Simply position the top dot directly above the bottom dot on the target and squeeze the trigger! Tritium inserts and photo luminescent front-sight outlines make these sights visible in all light conditions - day or night. GlockA(R) set features a green rear dot and a green front sight with a lime-green outline. Smith & Wesson (S&W) set has a green rear dot and a green front sight with an orange outline. Mfg: Ameriglo SPECS: Machined steel, matte black finish. Fits factory dovetails. GlockA(R) - .199" front blade height. Fits models 17, 19, 22, 23, 24, 26, 27, 33, 34, 35, 37, 38 and 39. S&W - .159" front blade height. Fits S&W M&P.