【Hands-Free Calls】: Bluetooth 5.1 technology provides stable wireless connectivity for smoother audio streaming and lower latency.With advanced noise-cancellation technology,Our in-car Bluetooth FM transmitter has a built-in high quality microphone, which can answer, reject, hang up and redial calls with one button, in addition, it can also play navigation, Siri Smart Assistant, and more from your mobile app program； | 【Dual Port Fast Charging】:This Bluetooth car adapter offers PD 20W and QC 3.0 18W dual-port charging capabilities,You can charge your phone, smartwatch, or tablet from 0% to 80% in 30 minutes,equipped with over-current, over-voltage, over-charging, overload, overheating and short-circuit protection to ensure safe charging on the go; | 【3 Music Playback Modes】:This Bluetooth transmitter can play music on car stereo through Bluetooth/USB drive (≤ 128GB)/SD card (≤ 128GB). Support WMA MP3 WAV APE FLAC music format; | 【Connection Steps】:1. Start the car and insert the product into the cigarette lighter; 2. Turn on the car radio and select an idle FM channel; 3. Press and hold the main button to enter FM mode, rotate left and right to adjust frequency; 4. Set the FM transmitter to the same FM channel as the car radio; 5. Turn on Bluetooth on the device, search for 'BT25' and connect.（Please note: Frequency 87.5-108.0 MHz）； | 【After-Sale Service】:If you encounter any connection problems or usage issues, please email the AOSITING store for a solution first, and we will be sure to provide you with a satisfactory solution.