Unique AUTO Button-By lightly pressing the AUTO button, you can quickly search for the best FM frequency, which greatly improves the automatic scanning speed and avoids frequent switching. Long press the AUTO button,it will turn off. Connect the wireless FM smart transmitter to Bluetooth and enjoy a full-range stereo music conference!Bluetooth V5.1 &Voltage Monitor-Bluetooth V5.1 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.PD & QC 3.0 Fast Charge-The car Bluetooth adapter can charge two devices simultaneously. 24W PD Type-C port and 18W QC3.0 port enables you to charge your device in 4X faster than standard chargers. 2 USB ports provide faster, more efficient charging for you.LED Ring Light&Heat Dissipation Hole-The Bluetooth FM transmitter can quickly dissipate heat through the heat dissipation hole, keep it in good working condition, and avoid damage to the device caused by problems such as overheating and short circuit. The LED ring light flashes with the music rhythm making it easier for you to operate in dark environments and keep your safety when driving.