Knights Armament Company URX 3/3.1 12 Piece Rail Panel Kit, Black Finish, 1 1-Hole Handstop, 3 2-Hole Panels, 2 2-Hole Panels, 2 3-Hole Panels, 1 2-Hole handstop, 3 2-Hole Picatinny Rail Sections, 10 Screws, 5 Backing Nuts 30409-BLK