Meprolight Tru-Dot AR-15 Front Post Night Sight, Front Only.
The ML31615 is a front sight only for use on AR style A1 and A2 rifles. This sight has a round front post, which is much narrower than the square post currently coming on the AR rifles. This thinner post gives more accuracy since it does not cover as great an area of the target at distances. The ML31615 are two-piece for alignment. Once you have the rifle sighted in for a particular distance, should the tritium light source not be facing you, all you do is depress the detent and rotate the sight to align the light source.
All Tru-Dot sights are covered by a 5 years usable illumination warranty to the original purchaser.