Nitrous Express Gasoline 50-300HP Jet Pack for Dual Holley Nitrous Plate KitNX Jets are manufactured on CNC equipment, and are guaranteed to be within . 0005 of specified jet size. In recent testing, using the same jet size, NX jets out flowed the competition by 35 percent! That is right 35 percent more flow through the same orifice, how you ask? The NX jet was designed to be more than just a hole in a piece of brass; its contoured inlet and multi stepped outlet allow turbulence free flow with no restrictions.