The continuous top rail allows you to mount iron sights, optics and any other accessories without additional rail sections. The M-Lok system allows users to customize the handguard with rail sections and direct mount accessories. The handguard is constructed of 6061-T6 aircraft aluminum and finished with a Mil-Spec type III hard coat black anodizing. The MLA has a precision bore to fit the proprietary barrel nut which removes any unwanted play and ensures an exact fit!! Installation requires a 1-1/8" crows foot wrench (not included) for the barrel nut; standard AR-15 barrel nut wrenches will not work with this handguard system. The handguard is secured to the barrel nut by 2 10/32 allen screws, stainless steel key seat lock, and anti-slip helicoils. PLEASE NOTE: AVAILABILITY AND DELIVERY ARE CONTINGENT ON SUPPLIER