The Spike's Tactical LW BAR2 is a 1-piece free floating quad-rail that is machined from 6061-T6 aluminum with a barrel nut machined from 7075-T6 aluminum and finished in type III hardcoat anodizing on the rail and barrel nut. The main benefit of the BAR rail is to those who wish to have a suppressor inside of the rail. The BAR rail also offers excellent heat ventilation built in anti-rotation tabs to keep the rail and even the barrel nut from coming loose. Features: Black finish 13.5 inches BAR2 free floating rail Fits AR rifles