This product design testifies to a clear knowledge of car battery voltage and the use of electrical appliances. It is suitable for use in 99% of car cigarette ports. Innovative features include a built-in intelligent voltage detection chip and real-time monitoring of the vehicle battery voltage through clear digital tube display. It can intelligently adjust the output current of two USB ports, display the electric current of the electric equipment in real time, and has an in-built alarm function if the current is too high.