NGK PTR5D-13 / PTR5D13 / 6644 Laser Platinum Spark Plug Replaces OE029 RES9PYP4 PT16EPR-L13 ( 6644 )OE Platinum spark plugs offer high ignitability and longer service life. Dual platinum surfaces ensure a slow wear rate providing stable idle, superior anti-fouling, improved fuel efficiency and lower emissions. Laser-welded platinum center electrode tip Platinum disc welded to backside of ground electrode provides long life Trivalent metal plating provides superior anti-corrosion and anti-seizing properties Faster starts and quicker acceleration Better fuel economy and lower emissions Best platinum 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.