Premium OE-grade spark plugs engineered for optimal ignition performance in Smart vehicles. Precision-crafted copper core with nickel alloy electrode ensures superior conductivity and extended service life. Triple gasket sealing system prevents combustion leaks and maintains consistent cylinder pressure. Direct OEM replacement for seamless compatibility with models requiring A1321590003 or A1321590103 parts. Ideal for urban commuters seeking reliable cold starts and fuel efficiency in compact engines. Factory-calibrated 0.8mm gap guarantees precise spark timing without adjustment. Ceramic insulator withstands extreme thermal cycling from -30°C to 1000°C. Includes anti-corrosion plating for coastal or winter driving conditions.