The durable Iridium IX Spark plugs, which enable complete fuel ignition in the combustion chamber via the spark they create, are built to last between 40,000 and 50,000 miles. UPGRADE YOUR RIDE: level up over OEM, V-Power, G-Power, and standard grade plugs with the NGK Iridium IX Spark Plug that provides superior performance and durability.
Premium product offering excellent performance. Fuel economy went from mid 30's to over 41 mpg on my 1978 XS1100. Your mileage may vary depending upon your riding style...