Plasma Spark is a spark plug boot (socket) specially designed and developed for SUBARU, which has an additional electrostatic capacitance, providing intense sparks at a microsecond rate and increasing ignition energy. All our products are made in Japan with high quality, reliability and safety unrivaled in the industry. Plasma Spark is also OBD II (On-Board-Diagnostics) compliant. Installation is easy. Simply replace the stock boots with our Plasma Spark Boots and all done!