Knight's Free-Float RAS replaces the standard hand guards on the AR15. The Low-Profile Gas Block may be required to replace the standard fixed iron sight. Installation requires removal of the barrel, flash suppressor and front sight/gas block. Picatinny rails on all four sides allow endless possible mounting solutions for accessories such as sling mounts, a bipod, vertical forearm grips, flashlights and more. The RAS comes with three 11 rib panels to help protect the rails from damage.