Denso's Iridium Saver industrial spark plug guarantees high reliability for withstanding high combustion pressures by incorporating a stress resistant monolithic resistor that adheres to the resistor glass in a high temperature furnace. This eliminates interference to electronic equipment from high energy coil noise. Newly developed ceramics with finer grain, molded in higher pressure and higher density prevents electrical breakdown of insulator. Special nickel plating with better corrosive resistance for condensed acid water. Four small electrodes create a cross groove which improves sparking performance and suppresses dispersion in voltage value, for an outstanding decrease in required voltage. Denso's unique iridium alloy offers a high welding point which dramatically improves wear resistance compared to other iridium plugs. 360° laser welding is used to create a seal so reliable the electrode resists wear even under the most extreme engine conditions. 0.7mm center electrode dramatically improves ignitability.