Wireless Bluetooth Car FM Transmitter MP3 Player Radio Adapter Kit USB Charger Features： This FM transmitter supports 3 playing sources: Bluetooth, TF card and U Disk. Dual USB charging ports-can fast charge for your phone. LCD Large Screen Display. Crystal Sound Effect - This FM transmitter utilizes the most advanced interference and noise cancellation technology, which provides crystal sound quality and more stable signal. Hands-free calling. Wireless transmit phone call from Bluetooth mobile phone to the car FM stereo system. Support MP3/WMA format and support TF Card in up to 32G.  Wide Compatibility - Our wireless fm transmitter car kit works with iPhone, iPad ,  HTC, Samsung Galaxy,  MP3 Players and other mobiles, save time. Specification: Rated working voltage: 12V~24V Limit working voltage: 9-30V USB output: 5V/2.1A Music format support: MP3、WAV MAX capacity of U-disk and TF card: 1G-32G Bluetooth version: Version 5.0 FM frequency: 87.5MHz-108 MHz Effective distance of mic: 0.5-2M Bluetooth transmission distance: ≤5M FM mode: Stereo digital PLL frequency lock Bluetooth sound processing A2DP (Advanced Audio Distribution Mode)function support      Button functions: Play/pause: press call button to play, press again to pause. Adjust volume: long tap "+"  key to up the volume, long tap "-" volume key to down the volume. Select music: press right volume key to play next song, left one to play previous song. Answer/end call: press call button to answer call, press again to end call; long tap call button to reject the incoming call, double click call button to redial. Package include： 1x FM transmitter 1 x User Manual