What sets the M4 RAS aside from other 2-piece quad rails available is the fact that it securely locks for the rifle’s barrel nut through a clamp and screw arrangement, which makes it an exceptionally solid foundation on which to mount tactical extras. Contains three KAC 11 Rib Rail Panels. https://kac-m4-ras64073.get-blogging.com/27186629/new-step-by-step-map-for-knights-armament-rail