[Bluetooth V5.0 Voltage Monitor]-Bluetooth V5.0 chip ensures a faster data transmission rate and more stable connection. Automatically connect memorized paired when power on. This FM Transmitter with digital display also can detect and display the voltage of car battery after power on. [Double USB PD Charging Port]-Equipped with 2 USB ports and one PD charging port, the car charger can charge 3 devices simultaneously. The charging speed becomes faster and more effective.3 USB ports can be used to solve the charging problem of multiple mobile devices easily. [Safe Hands-free Calls]-Built-in microphone with noise reduction technology to create clear sound quality, which offers you convenient hands-free talking and smart broadcast navigation. It is carefully designed for your answer/hang up/reject a call/redial the last number via the multifunctional button to keep your safety when driving. [3 Playing Modes Hi-Fi Sound]-This Bluetooth car radio transmitter has 3 music playing modes including Bluetooth connection, TF card and USB disk. It supports MP3 / WMA / WAV/ APE / FLAC format files and Hi-Fi stereo system. It adopts DSP and A2DP dual-core technology, you can enjoy high-quality music and communication.