USB interface: The USB interface is used for power supply. When in use, connect this product to a USB port with an output voltage of 5V, such as a car USB port (5V) or a car charger (5V). Specifications: Multi-function button: 1. Adjust the FM frequency. After powering on and pairing via Bluetooth, press the button to switch between available FM frequencies (87.5MHz, 95.0MHz, 103.0MHz). 2. During music playback, press the button to pause or play. 3. Answer or end calls: when receiving a call, press the button to answer or terminate the call. Instructions: 1. Plug the FM01 into a 5V USB port in the car. 2. Press the button to set the desired FM frequency, then turn on the car radio and tune it to the same frequency as the FM01. 3. The FM01 has an automatic frequency memory function and will default to the last used frequency upon power-up. 4. After setting the FM frequency, go to the Bluetooth settings on your mobile device, select the device named "FM01", and complete the pairing. o will then be played through the car speakers. 5. Adjust volume: set the phone's media volume to maximum and control overall volume using the car’s o system. Avoid setting the car speaker volume too high, as excessive volume may cause noise and o distortion. This product is designed for in-vehicle use and features Bluetooth 5.1 technology and FM transmission to enable wireless o streaming in cars. Parameters Product name: USB Bluetooth FM transmitter Product model: FM01 Bluetooth version: V5.1 Working voltage: 5V Effective range: up to 10 meters o output: FM transmitter Default frequency: 95.0MHz Signal-to-noise ratio: 95dB Call function: supported Auto return: supported Power supply: USB powered (5V) Color: black Material: plastic Package Contents: 1 x Car Bluetooth FM Transmitter Note: The package includes only the items listed above; other accessories are not included. Note: Lighting conditions and display settings may cause slight color variations between the image and the actual product. Measurement error is permitted within +/- 1-3 cm.