The Samson Manufacturing Evolution Series free float rails are customizable AR-15 handguards. The Evo rail attaches to a standard barrel nut with a two piece thermal bushing constructed of stainless steel, two locking tabs ensure the rail does not rotate under stress. The thermal bushing along with the generous ventilation slots help to keep heat from transferring into the handguard and into the operator's hand. The continuous top rail allows you to mount optics anywhere along the top of the rifle and allows same-plane iron sights to be mounted. The top rail has also been relieved to accept most aftermarket piston conversion systems. Each Evo handguard includes two 2", and one 4" customizable rail sections that can be mounted anywhere along the handguard tube. The interior of the tube is 1.56" in diameter, allowing most suppressors to fit underneath. The EVO Extended Rail series feature a front sight cut out, so the lower portion of the handguard extends out past the ...