FAST Air/Fuel Meter Dual Sensor Kit WirelessFAST's wireless, dual sensor technology measures your engines air fuel ratio with precision accuracy, all from the convenience of your smart phone! FAST has revolutionized the tuning industry with the most advanced, App based, wireless, air fuel meter. The FAST Wireless Air Fuel Meter uses an underhood mounted Bluetooth module, connected to oxygen sensors in both of your engines exhaust outlets, giving you the full story on the state of your engines