Knights Armament Co.’s Free Float RAS (Rail Adapter System) features full length mil-spec M1913 Picatinny rails at the 12-, 3-, 6-, and 9 o’clock positions, making it compatible with any number of rail-mounted tactical accessories. The rail free floats the barrel, allowing for consistent barrel harmonics upon firing, and thus increased accuracy potential. The MRE kit is designed to work with M4 carbines, and accommodates a fixed A2 front sight tower with carbine length gas system. It extends past the front sight base, providing additional rail space for the mounting of tactical accessories. Includes three KAC 11 Rib Rail Panels.