Audio Receiver and AUX Output: Adjusts the FM transmission frequency to match your car radio's frequency (frequency range: 87.5-108.0MHz). AUX audio supports lossless input.[Upgraded Bluetooth 5.3 Technology] The latest Bluetooth 5.3 technology optimizes transmission delays and connection defects. Bluetooth 5.3 provides a faster, more stable, and smarter connection with less sound quality loss, ensuring uninterrupted calls and music. Pairing takes just 1 second, eliminating the need to re-pair after the initial successful pairing.[Smart Dual USB Ports and Fast Charging] Equipped with two USB ports (PD 30W and USB A 12W), it can charge two devices simultaneously. Built-in overcurrent protection, overvoltage protection, intelligent temperature control, and short-circuit protection ensure safe charging.[Clear Music Streaming] Bluetooth 5.3 provides a stable connection, while noise cancellation (CVC) technology and echo cancellation deliver an amazing hands-free calling experience. Additionally, this Bluetooth car adapter supports Bluetooth and USB flash drives (64GB). To use: Plug the T18/T02 into your car's cigarette lighter socket; the LED indicator will illuminate. Connecting to Bluetooth: Enable Bluetooth on your smartphone, select "T18/T02," and pair with it. Adjusting the FM transmitter frequency: Turn on your car's FM radio and tune the frequency on the T18/T02. Press and hold the multi-function dial button until the frequency display begins to flash; rotate the dial to adjust the FM transmitter frequency to match your car radio's frequency.