This product is designed for in-vehicle use and features Bluetooth 5.1 technology combined with FM frequency modulation to enable wireless music playback in cars. Product Name: USB Bluetooth FM Transmitter Product Model: FM01 Bluetooth Version: V5.1 Working Voltage: 5V Effective Range: Within 10 meters Audio Output: FM Transmitter Default Frequency: 95.0 MHz Signal to Noise Ratio: 95 dB Call Answering: Supported Auto Reconnection: Supported Power Supply Mode: USB power supply (5V) USB Interface: Used for power supply. Connect to any USB port with 5V output, such as a car’s built-in USB port or a car charger with USB output. Specifications: Multi-function Button: 1. Adjust FM frequency. After powering on and before Bluetooth pairing, press the button to cycle through available frequencies (87.5 MHz, 95.0 MHz, 103.0 MHz). 2. During music playback, press the button to pause or resume playback. 3. Answer incoming calls: Press the button to answer a call when receiving an incoming 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 device. 3. The device has an automatic frequency memory function and will recall the last used frequency upon power-up. 4. After setting the FM frequency, go to the Bluetooth settings on your phone, search for the device named "FM01", and complete the pairing process. Music from your phone will then play through the car’s speakers. 5. Volume adjustment: Set the phone’s volume to maximum and adjust the overall listening level using the car’s volume control. Avoid setting the car’s volume too high to minimize noise and distortion. Package Included: 1 x Bluetooth Adapter 1 x User Manual