Iridium Spark PlugNGK Iridium spark plugs currently represent the highest quality technical solutionThey feature an iridium alloy on the centre electrode, which is welded on in a special process using a laserThe precious metal iridium is one of the hardest metals in the worldIts melting point is 2450 °C and is therefore particularly resistant to spark erosionBy using this metal, the service life is doubled on average compared to conventional spark plugs made of nickel