What sets the M4 RAS in addition to other 2-piece quad rails in the marketplace is it securely locks towards the rifle’s barrel nut by using a clamp and screw arrangement, rendering it an exceptionally reliable foundation upon which to mount tactical equipment. Contains a few KAC 11 Rib Rail https://kacm4ras18417.blogzet.com/5-essential-elements-for-kac-rail-41164183