This item is a set of four (4) GENUINE NGK BKR9EIX iridium spark plugs. These are resistor type spark plugs that are a perfect compliment for your Coil on Plug upgrade. These spark plugs are available with a factory gap or a custom gap for your set up easily selected with the drop-down window above. Purchasing these directly from Burton Racing allows you, the end user, an extremely simple install with a standard spark plug replacement procedure. No fiddling, searching for tools or risking damage to your brand new spark plugs.