The NX original nitrous rails feature a billet aluminum body anodized in black. This package includes 2 double hole rails in black, 4 5/16 x 24 pipe plugs, 4 1/8" input fittings, as well as 16 5/16 x 24 - 3an fittings. These rails would be spectacular for those looking for a clean look while also using less space than the traditional distribution bocks. , , NOTE: Both ends of rails will require tapping for the necessary fittings., , First in Quality, first in technology, Nitrous Express, the Next Generation nitrous company!