TROY Industries BattleSight, Rear Folding Sight, Di-Optic Aperture, Tritium, Picatinny, Black Finish SSIG-FBS-TTBT-00 Advanced design" superior sighting and BattleReady(TM) toughness define Troy Industries' new Di-Optic Aperture (DOA(R)) 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.