The NGK Iridium IX spark plugs offer improved throttle response; superior anti-fouling and high-ignitability; which makes Iridium IX® ideal for the performance enthusiast; even better than platinum. Iridium''s extremely high melting point is perfectly suited to today''s high-temperature engines; delivering outstanding acceleration; fuel efficiency and double to triple the lifespan of a copper core plug. - Fine iridium tip ensures high durability and a consistently stable spark. - Trivalent metal plating for superior anti-corrosion and anti-seizing properties. - Outstanding acceleration; high fuel efficiency and durability.