Lightweight and comfortable, the Rise Armament slimline rifle rail features a smooth, thin center for enhanced grip and ease, along with a free-floating barrel design for enhanced accuracy. It comes equipped with a full length top rail, and short sections of Picatinny rail at the 3, 6 and 9 o'clock positions for the addition of accessories. Comes with barrel nut and mounting hardware. Inside diameter is 1.35".