Denso QJ16ARU Spark Plugs (4-Pack) - High Performance Iridium Spark Plugs for Toyota, Lexus, Scion | Perfect for Engine Tune-Ups & Fuel Efficiency Boost

U-Groove ground electrode design gives the flame a groove to grow in, resulting in less flame dissipation and a larger flame front for a more complete combustion. This translates to better fuel efficiency and improved throttle response

100 percent pre-fired to ensure reliable operation

Copper core center electrode for superior thermal conductivity

Unique five-rib insulator reduces flashover and decreases voltage loss

Dual copper and glass seal bonds the center electrode and insulator together for a gas-tight seal.

Original Equipment in automotive applications