Troy Micro BattleSights feature a rugged low-profile design developed for firearms with top rails higher than the standard M4. These sights are ideal for shooters who prefer a sightline that is as close to the barrel as possible, or for those with raised top rail systems. 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. Features: a Tritum illumination on front and rear sight. a When sights are folded, they lie paralell against the receiver reducing the chance to be damaged or broken. a Greatly enhances weapons such as the new IAR, the Sig Sauer 556A(R) Pistol and Carbine, POF 416A(R), FN ScarA(R), Robinson Armament XCRA(R), Heckler & Koch 416A(R) & 417A(R) and other weapons with raised top rails. a Sold as a set only.