Each and every spark plug manufactured by NGK is designed to meet the most rigorous standards, ensuring there ability to deliver reliability and consistent performance under all conditions. Each plug plays a major role in helping improve performance, fuel economy and the overall optimum efficiency helping to make a significant contribution in the reduction of emissions.Standard Copper Core plugs - NGK uses Copper wire in place of the iron core found in conventional plugs and is the secret to their wide heat range. The Copper core electrode provides superior heat conductivity, allowing quicker dissipation of heat and helping in the cooling of the electrode tip and insulator tip; thus preventing hot spots that could cause pre-ignition. Copper cored electrodes also mean that longer insulator noses can be used to protect against fouling!