Bosch Silver spark plugs are specifically engineered to improve your performance, whether sport-driving and racing conditions or power sport application. These fine wire performance plugs are specifically engineered for colder racing applications, particularly those that run at full throttle (racing, water ski, and towing) and not for traditional automotive use (stop and go traffic) as they would quickly foul out. At the heart of these plugs is the silver enhanced center electrode that conducts electricity better than copper or nickel. These plugs are specifically engineered for high performance, not long life. As silver has a lower melting point than nickel, these plugs will need to be replaced more often depending on your application. For many racing applications this is not an issue as many racers are already replacing plugs after each race or even every run.