WT OBD has a built-in GPS antenna and is a compact unit in small volume. Small ODB devices are easy to be installed and their antenna is difficult to be damaged. But the covers of the devices weaken the signals inevitably though this issue can be resolved by prolonging lines. WT OBD can check the automobiles to obtain the real-time running status and then determine the driving habit (e.g., rapid acceleration, rapid deceleration, sharp swing, and speeding) based on the statistics data with the help of the 3D sensor. In addition, it can precisely calculate the energy consumption and mileage. It supports standard OBD communications protocols.