Improved ignition performance, durability and anti-carbon build-up. The Ultimate spark plug for increasing performance of tuned or stock engines. Spark plugs become a key factor in clean and complete combustion in any petrol engine. Clean and complete combustion is paramount in performance tuning as the power produced is directly related to the force of the combustion. HKS offers a large range of spark plugs to accommodate a wide range of vehicles in varying different states of tune. New material and design improves durability, which allows for use under harder combustion conditions such as continuous high load during circuit driving or aggressive tuning. * Improper combustion condition or wrong heat range selection may cause damage to sparkplug.