Troy Industries' Tritium BattleSights(TM) are designed to eliminate the poor sight orientation that is typical in twilight. Tritium is a form of hydrogen that emits a continuous light source when batteries or electricity are not available. The front post is centered between two Tritium points of reference to allow proper alignment. Troy Rear Folding Tritium Sights"" a permanent"" rail-mounted alternative to a standard A2 sight"" allow limitless mounting options on all-length rails with a serrated ramp to eliminate glare.