The product is a set of four genuine NGK spark plugs with model number ZFR5J-11 and part number 5584. These spark plugs have a 14mm thread diameter and are designed for gasoline engines. They are made of nickel material and are considered performance parts, providing improved ignition efficiency for better engine efficiency and power output. The product does not carry a vintage part designation and includes a California Prop 65 Warning regarding nickel content. Please be aware that we have 2 in stock so if you order 1, you will get either box version of the 4 plugs.