Daniel Defense's DDM4 Rail utilizes an optimized, free-floating design which delivers the superior ergonomics, durability, and light weight that Daniel Defense is known for. It features four picatinny rails in the 12 o'clock, 3 o'clock, 6 o'clock, and 9 o'clock positions for the installation of tactical lights/lasers, fore-grips, and optics. This rail is also outfitted with limited rotation QD sling swivel attachment points on the front and back of for sides for ambidextrous use. In addition, this rail is compatible with low profile gas blocks on barrels 11 inches and longer with gas systems at mid-length and shorter. Features of the DDM4 Rail: Lightweight Free Floating Barrel DesignSteel Barrel NutUninterrupted Upper Rail PlatformIntegral Sling Swivel Attachment Points with Limited TravelPatented Bolt-Up SystemMil-Spec 1913 Picatinny Rails Daniel Defense DDM4 15.0 Rifle-Length 15.2" Free Float Quad-Rail Handguard 01-134-09186