Bosch (4301) FGR8DDP Platinum  Spark Plug The dimensions of this tip are 1.5 inch diameter and 6 inches long Revolutionary surface air gap firing technology featuring two yttrium-enhanced ground electrodes delivers a longer, more powerful spark for optimum engine performance Two yttrium-enhanced ground electrodes provide optimum access to the air/fuel mixture for more efficient combustion...plus a longer performance life More platinum in the center electrode further increases performance life Electrode gap is factory set to provide ease of installation never requires adjustment Provides ease of installation -- never requires adjustment