Genuine OEM Audi Spark Plug, part number 04E905601B. This critical component is responsible for generating the electrical spark required to ignite the air-fuel mixture within the engine's combustion chambers, initiating the power stroke. It is installed in the cylinder head, with its tip extending into the combustion chamber. Weighing 0.044 kg, this spark plug is engineered for precise heat range and electrode gap. Choosing a genuine OEM spark plug ensures correct thermal characteristics, optimal ignition timing, and resistance to fouling, which are vital for engine performance, fuel efficiency, and emissions control.