The Daniel Defense DDM4 Rail features an optimized one-piece, free-floating architecture. This design results in the ergonomics and proven durability users demand while maintaining the lightweight characteristics they expect from Daniel Defense.The DDM4 Rail's ergonomic design allows operators to maintain better control of the firearm. Limited rotation QD swivel attachment points are located at the front and rear of both sides of this rail system for tangle-free attachment for slings. A continuous Picatinny rail on top provides the rail real estate for sights and accessories.DDM4 Rail 12.0 rail system is designed to be used in conjunction with a low profile gas block on either a carbine or mid-length gas system.Rail System includes all required hardware (Barrel Nut, Bolt-Up Plate, & Screws), tools (Barrel Nut Wrench & Allen Wrench), and 3 Daniel Defense Rail Ladders made of high-temperature resistant Santoprene. Key Featuresa Lightweight Free Floating Barrel Designa Steel Barrel Nuta Uninterrupted Upper Rail Platforma Bolt-Up Systema Mil-Spec 1913 Picatinny Rails