Diamondhead Diamond "Gas Block" Front Sights857880003092 Diamondhead's Diamond "Gas Block" Front Sights (for AR15 & AR10) mounts directly to an existing railed gas block of the reduced gas block height. The gas block sight comprises a proprietary Diamondhead sight base (of increased height to compensate for the lower gas block) and a patented Diamond shaped upper sight housing. Features Rail mounted, Diamond folding sight incorporating the patented Diamond shaped upper housing Mounts directly