Spark Plugs are a critical engine component that provides the spark that ignites the air-fuel mixture that drives an engine. NGK Spark Plugs feature a trivalent plating, a silver-or-chrome colored finish on the threads is designed to provide corrosion resistance against moisture and chemicals.
The semi-superficial discharge type spark plug is designed to produce sparks along the isolator surface in the metal cover direction. The sparks burn the adhered coal, providing this way greater resistance against dirty.