Diamondhead's Polymer Integrated Sighting System is designed for all AR15s and Modern Sporting Rifles. Front and Rear Sights both incorporate the Patented Diamond-shaped apertures for faster target acquisition & centering and upper housings are fitted with NiteBrite photo luminescent inserts. (the inexpensive alternative to Tritium) Suitable for firearms fitted with a Diamondhead VRS hand guard OR any M1913 Picatinny Rail System. Also has an and accurate 0.5MOA windage adjustment. (NOT SUITABLE FOR GAS BLOCK SIGHT BASES - due to heat issues) Lifetime Warranty. Fit's AR-15, M4, M16, Armalite, Colt, Smith & Wesson, Sig Sauer, HK, Stag, Daniel Defense, Bushmaster, DPMS, Rock River Arms, BCM, CMMG..