Fusion spark plugs feature a patented, fused iridium and platinum center electrode, combined with exclusive surface air gap firing technology to produce a longer, more powerful spark. Their four yttrium-enhanced ground electrode design outperforms OE iridium plugs by significantly reducing gap wear. This means less stress on the ignition system for quicker starts, more efficient fuel combustion, and a longer performance life. In addition, Fusion's voltage requirement increases less over time versus other iridium plugs for longer reliable performance of the vehicle's ignition system. Sold individually