FAST's Wireless, dual sensor technology measures your engine’s 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 engine’s exhaust outlets, giving you the full story on the state of your engine’s tune. With the FAST Wireless Air/Fuel Meter, you can read both wideband oxygen sensors individually, or average them together for super accurate readings of the engine’s true air/fuel ratio. For engine tuners on a budget, a single sensor version is also available. Easy to use with any iOS or Android device, the FAST Wireless Air/Fuel Meter App includes a simple, built-in data-logger that records up to two minutes of air/fuel and rpm data. Fuel calibrations are pre-loaded for measuring Gasoline, all popular Ethanol blends, Methanol, Diesel and more. Advanced App/Module features include 0-5 volt output for external data-loggers and digital gauges, an rpm activated window switch and a lean air/fuel ratio safety cut-off. Additionally, an innovative Anti-Theft feature has been incorporated that allows you to manually activate/deactivate a vehicle immobilizing relay. A simple way to protect your vehicle from theft! With features unlike anything else on the market, it’s clear the FAST Wireless Air/Fuel Meter is the best choice for the serious engine tuner.