The Denso 5346 Spark Plug is a high-quality product that offers many features to maximize the potential of your car's engine. The 0.4 mm iridium center electrode is the world's smallest diameter that maximizes firing potential. The U-groove and taper cut ground electrode provides faster spark flame growth and lessens heat quenching. The DENSO patented 360 degree laser welding process ensuring exceptional quality bond and structural streng.