l The Free Float Quad Rail features a host of upgrades over the standard M4 drop-in quad rail system found on many US military rifles. l The barrel nut also serves as screw on base for the outer rail sleeve and is secured by a steel locking ring. l The rail utilizes four MIL-STD 1913 rail systems as a mounting interface and incorporates radial cutouts along the length of the rail to lower overall weight. l Hard Coat Anodized Finish