As mentioned, Effuel is a small chip that can connect directly to your car via the OBD2 port. All modern cars have an OBD2 port. The OBD2 port is directly connected to the car’s Engine Control Unit (ECU), which controls everything in a fuel injected engine. This includes the air fuel ratio, valve timing, idling speed, and rev limiter. Each car’s ECU is pre-programmed (known as “the map”) by the car manufacture.Due to various factors like fuel grade or oxygen concentrations, the efficiency of the engine can drop since the original map was not made for these circumstances. What this device does is analyze the data collected by the sensors of the car and “remap” the ECU to perform more efficiently once it is connected to the OBD2 port. The changes it makes are temporary as the ECU switches back to the stock map when EcoOBD2 device is removed.Click Here https://www.globenewswire.com/news-release/2021/04/12/2208677/0/en/Effuel-Reviews-2021-Effuel-Eco-OBD2-Device-Fuel-Saver-Chip-for-Sale-By-iExponet.html