The F.A.B. Defense FXNFR NFR Quad Rail for Carbine Length M16 1913 Mil-Spec Picatinny Rails Black Anodized Aluminum delivers a robust M4 replacement forend that adds four mil-spec Picatinny rails for versatile accessory applications, enabling you to customize optics, grips, lasers, and illumination with precision. Precision machined from 6061 T6 billet aluminum, this quad rail offers maximum strength while maintaining a slim profile for better grip and handling, and its hard coat anodized finish provides optimum wear resistance for field durability. The fully rugged construction resists bending or deformation under demanding conditions and has been field tested to ensure reliable performance across extreme environments. Simple installation replaces the polymer hand guards and is secured by four bolts, with the rail system firmly locking to the barrel nut and front hand guard cap, and no gunsmith is required. Receiver alignment is achieved through anti-rotation locking tabs, ensuring the upper rail aligns perfectly for consistent accessory mounting. This rail system integrates seamlessly with carbine-length setups, enhancing versatility for tactical, hunting, and range applications while maintaining a lightweight, balanced feel for improved control and handling.