Zex is at the forefront of nitrous technology with its innovative wet nitrous system. The Zex system incorporates the most technically advanced performance features available, including the patented zex active fuel control. This innovative performance and safety feature automatically adjusts the nitrous fuel enrichment so your engine never runs too rich or too lean. In addition, the zex nitrous system features a patented electronic tps switch for perfect system ativation at wide open throttle. All the kits primary components, like the solenoids, filters, and activation electronics, come factory pre assembled inside an enclosure called the nitrous management unit. The zex kit is a simple 2 hour installation. The part number for this item is 82021 and it fits 1994-2010 Mazda Miata models.