The Autolite 104 Spark Plug Set of 4 is a high-quality ignition system component designed for gasoline engines. Made with copper material and featuring a 14mm thread diameter, these standard configuration spark plugs are backed by a 1-year manufacturer warranty. With a focus on reliable performance, these spark plugs are suitable for everyday use in vehicles. Additionally, they are designed to meet California Prop 65 Warning standards for nickel content. Upgrade your car's ignition system with this all-American made spark plug set from Autolite.