Upgrade your vehicle's ignition system with this set of 6 Splitfire SF516D Copper Spark Plugs. These spark plugs have a 14 mm Thread Diameter, a Standard Configuration, and a 16 mm Hex Size. They are made of high-quality copper, which provides excellent conductivity and durability for long-lasting performance. These spark plugs are compatible with a variety of vehicles, including the Grand Prix, LandRover LR3, and Mazda 6 B300. They are Performance Parts that can replace OE/OEM Part Number 19157998 and Interchange Part Numbers VT20, SF524E, 5245, AGSF43CF4, IT20, and RS15LYC. Made in the United States, these spark plugs are designed to deliver reliable ignition and optimal engine performance.