NGK IMR9D-9H / IMR9D9H / 6544 Laser Iridium Spark Plug Replaces VHN27Z With the smallest tip diameter available, OE Iridium spark plugs provide superior ignitability and long service life. The iridium/platinum surfaces ensure a slow wear rate, providing stable idle and superior anti-fouling. Laser-welded iridium center electrode tip Platinum disc welded to backside of ground electrode provides long life Trivalent metal plating for superior anti-corrosion and anti-seizing Faster starts and quicker acceleration Better fuel economy and lower emissions Best OEM Iridium spark plug available OEM-approved designBOX 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.