NGK Spark Plugs (U.S.A.), Inc. is the largest OE supplier and manufacturer of spark plugs, oxygen sensors, and A/F sensors for domestic and import vehicles in North America.All NGK Spark Plugs must pass extensive testing procedures and quality checks throughout the manufacturing process to ensure fit and performance.-Mechanical vibration testing-Thermal shock testing to -40 degrees F-Tightest resistor manufacturing process in the industry-Manufacturing in our ISO 11565 certified facility-Gap measured with laser precision throughout production process. High-grade alumina silicate ceramic - Creates a stronger insulator to reduce dielectric punch-through (caused by spark exiting through the side of the ceramic).Corrugated ribs - Prevent "flashover" of spark, which can lead to harmful misfires and rob you of performance.Solid copper core along with NGK's high grade pure alumina ceramic enables the spark plug to quickly dissipate large amounts of heat. This ultra-wide heat range prevents spark plug overheating while providing reliable starts.Triple gasket sealing process - Virtually eliminates the possibility of combustion gas leakage back through the metal shell.Longer insulator nose - This superior design, sometimes called a "power tip" prevents loading up or fouling, even after prolonged periods of idling, or at slow speeds.Trivalent metal plating - No anti-seize required.Cold-rolled threads - Prevents cross-threading and damage to cylinder heads.