General description Bluetooth FM Transmitter Car Adapter allows you to enjoy hands-free calls and stream MP3 music or audio from apps while driving. It features a 1.8-inch color screen, three USB chargers, and a 3.5mm AUX port, making it compatible with various devices including iPhone, iPad, Samsung, and more. Technical specifications Screen: 1.8-inch color display USB Ports: 3 (including QC 3.0 dual USB charging) AUX Port: 3.5mm Battery Voltage: Normal range before starting the car: 12.8V-12.2V; after starting: 14.8V-13.4V Installation Plug the FM transmitter into the car cigarette lighter socket. Set your car radio to a blank frequency. Press the adapter "CH" button to display the channel. Adjust the FM transmitter frequency to match your car radio. Press the "CH" button to fix the frequency. Pair the FM transmitter with your phone via Bluetooth or use a USB/TF memory card to play music or make calls. Usage To answer a call: press the answer key. To decline a call: press and hold