The AC Delco Spark Plugs S41F Set Of 4 is a vintage part made of copper, designed for gasoline fuel type vehicles with a thread diameter of 14 mm. These spark plugs are manufactured by ACDelco, a trusted brand known for high-quality automotive parts and accessories. Ideal for car and truck owners looking for reliable ignition system components, these spark plugs are sure to help improve the performance of your vehicle. (Estate sale)