Multi-Ground Electrodes Improve Ignition Capabilities and are Less Sensitive to Increased Voltage Requirements Due to Gap Growth.Designed to Specific Manufacturer Ignition Requirements, NGKs Multi-Ground Plugs Maintain All the Features of Their Standard Plugs, Including:Corrugated Ribs to Prevent FlashoverPure Alumina Silicate Ceramic Insulator, Providing Superior Strength and Better Heat TransferCopper Core to Aid in Heat RemovalTriple Seals to Prevent Leakage