Laser Iridium Compared to Standard Spark plugs, NGK Laser Iridium provides a superior fuel burn combined with a longer service life. With 6.5 on the 'Mohs' hardness scale, Iridium is the second-densest element to exist (after Osmium), yet it's also the most corrosion-resistant metal (even at temperatures as high as 2000? C ). Thanks to Iridium's excellent electrical conductivity properties, it's the perfect metal element to include in the manufacture of premium spark plugs. The laser welded platinum disc on the ground electrode provides extra durability, once again improving service life and bringing the wear rate down to a minimum. With both electrodes working in harmony together, your engine will have a more stable idle with superior anti-fouling, improved fuel efficiency and lower emissions. Another great feature is that the ground electrode is also taper cut, in simple terms, this is done to reduce as much obstruction as possible to the flame expansion (this reduces quenching) as it starts to burn from the electrode tips. This allows for a more complete, efficient burn which in turn increases MPG. Features Laser welded Iridium centre electrode tip Laser welded Platinum disc on the ground electrode Trivalent metal plating for superior anti-corrosion and anti-seizing properties Faster starts and smoother acceleration Superior anti-fouling Lower required spark voltage, great for those colder mornings Tapered ground electrode improves flame expansion from the initial spark Better fuel economy and lower emissions Factory fitted equipment in many of today's vehicles (OEM Approved Design) Outstanding quality as you come to expect from NGK. Proven track record and used in millions of vehicles around the world.