NGK IRIDIUM Series IRIWAY8 [Set of 4] [STOCK NO.] 4882 Spark Plug8 Fomula1, a top power that lets you get close to MotoGP racing! Tune up your car with the IRI series! [NO. 1] Improved startability and acceleration: Bringing the technology cultivated in Formula 1 and MotoGP to you. Iriseries plugs are high performance plugs that spread flame faster and have less energy loss (extinguishing effect) than regular plugs. [NO. 2] Engine power up: Top teams in the world use NGK plugs. This track record speaks for itself.