For a simple upgrade that can make a real difference in how your engine runs, consider these DENSO Iridium Power spark plugs. This is a 4-pack of genuine DENSO plugs, part number 3421 (also called SK20HR11). The iridium center electrode is incredibly fine, which allows for a stronger, more focused spark for better combustion. This can translate to smoother idling, better throttle response, and even improved fuel efficiency in some vehicles. Iridium is also one of the hardest and most wear-resistant metals, so these plugs are designed to last a long time – often much longer than standard copper plugs. They come pre-gapped from the factory for specific applications. Just make absolutely sure this is the correct plug for your car's year, make, model, and engine before ordering. A straightforward maintenance item that delivers top-tier performance.
