[Bluetooth V5.0 Connection]: Bluetooth 5.0 transmission technology allows fast connection and stable signal. Automatically connect memorized paired when power on. Rotate function button allows you to easily select FM channels and Play / Pause / Answer / Hang up phone calls. [Dual USB Port Safe Charging]: It has two USB charging ports, it can charge two devices at the same time and has overcharge protection. The device is safer when charging. The fm transmitter with bulit-in smart chip will divide the voltage based on the need of device automatically. [Easy to Use]: Plug car audio fm transmitter into the cigarette lighter socket, set the Car FM Radio to an empty station (87.5-108.0 MHz) and tune the FM Transmitter to the same frequency. Pair your phone and fm transmitter via Bluetooth, and then enjoy your music [Hands-free Calling]: Built-in microphone with CVC noise reduction technology to create full duplex sound quality offer you hands-free talking and navigation voice broadcast. Just press the button to answer/ hang up/ reject/ redial calls, seamlessly switches between incoming calls and music. your hands can be free for safe driving. [Widely Compatibility]: Bluetooth Car FM Transmitter is compatible with most Bluetooth enabled devices, supports play music via Bluetooth, TF card and USB disk and it will automatically detect and play the MP3/WMA/FLAC/WAV/APE format music .Widely compatible between any devices which support bluetooth and cars in 12-24V.