BRISK USA DR15SXC Spark Plug, DR17SXC Latest technology laser multi-spark plug, 14mm thread, 19mm (3/4") reach, gasket seat, 5/8" hex Designed to replace factory installed spark plugs in auto, motorcycle, ATV and marine applications For performance/race use DR15SXC Fire in 360 degree at place of best air/fuel mixture-spark not confined in one predetermined location Better utilization of available combustion energy - better performance and fuel utilization