The 4 pc DENSO 3517 Iridium Spark Plugs FC16HR-CY9 are genuine spark plug kit from trusted brand DENSO. These spark plugs are made of nickel material, designed for direct replacement, and come with a 1 year manufacturer warranty. With a standard configuration and free core charge, these spark plugs offer reliable performance for your vehicle's ignition system. Perfect for car enthusiasts looking for high-quality components to ensure optimal engine function.