Included with the MK14 Super Modular Rail is an updated version of the proven Geissele Barrel Nut design, not only providing ease of installation but superior rigidity. The long surface contact of the 2.25" barrel nut interfaces with the receiver creating a platform that can be trusted to be straight and true the entire length of the free float rail. The MK14 is 3d precision machined using 6061-T6 Aluminum due to its strong, rigid and lightweight properties. Utilizing Magpul's M-LOK technology in the 3, 6, and 9 o'clock positions allow the end user full customization and modularity of their rifle to securely mount lights, bipods and other firearm accessories. The Geissele MK14 Super Modular rail is finished in a durable and long lasting Type 3 Hardcoat Anodized.