Diamondhead USA Front and Rear Combat Iron Sights - Integrated Sighting System (Sold as Set) FLIPS UP QUICKLY and smoothly for rapid deployment REAR SIGHT: Patented diamond-shaped apertures for FASTER TARGET ACQUISITION & centering; proprietary reference posts and horizon bars FRONT SIGHT: Patented diamond-shaped housing; accepts all standard A2 front sight posts " SECURE AND ACCURATE 0.5 MOA windage adjustment FULLY DEPLOYS AND STOWS with small or large aperture active