Advanced design superior sighting and BattleReady? toughness define Troy Industries? new Di-Optic Aperture (DOA®) flip-type sights. Now available with Tritium a form of hydrogen that emits its own light source ideal for any low-light shooting situation.These sights provide lightning fast target acquisition and are manufactured to exceed military specs. The optically engineered apertures center your eyes instantly and effortlessly providing a clearer target picture than with round apertures.The sights feature two settings one for up to 300 meters and a second for up to 550 meters. This versatility makes the DOA ideal for military law enforcement and home defense applications. These advanced sights have been extensively field-tested and like all Troy Industries products are BattleReady. Count on it.