NGK Iridium Spark Plugs 6994 (IZFR6K11) http://amzn.to/2fCEsp3

NGK (6994) Laser Iridium Spark Plug
Designed to operate over a much wider heat range than ordinary plugs
Resists carbon buildup and preignition
High alumina ceramics for better heat transfer and electrical insulation
Solid copper core and nickel tipped electrode provide a longer plus life
Patented triple gasket sealing process eliminates the possibility of combustion gas leakage
Laser welded Iridium center electrode tip ensures high durability and greater spark
Platinum disc welded to backside of ground electrode provides long life
Longer insulator nose prevents fouling, Corrugated ribs on insulator prevents flashover, and the triple gasket seal eliminates combustion gas leakage
Faster starts and quicker acceleration
Better fuel economy and lower emissions, Trivalent Metal Plating for superior anticorrosion and antiseizing