NGK CR9EIX / 3521 Iridium IX Spark Plug Replaces OE122 RG4PHP IU27 IU27 Designed specifically for the performance enthusiast, Iridium IX offers extreme ignitability, improved throttle response and superior anti-fouling. Fine iridium tip ensures high durability and a consistently stable spark Iridium alloy has extremely high melting point, perfect for todays high-tech, high-performance engines Trivalent metal plating provides superior anti-corrosion and anti-seizing properties Outstanding acceleration, high fuel efficiency and durability Ultimate design, technology and performanceBOX DIMENSIONSHeight (mm): 85Width (mm): 24Length (mm): 22 If you are unsure as to whether this is the correct part for your vehicle, please don\'t hesitate to contact us. Alternatively please use the cross reference table above.