Features Bluetooth hands-free calling, USB port with charging function 3.1A Echo and noise processing during a call; Stereo Bluetooth and FM transmission technology Support USB/TF card/Bluetooth connection; Support MP3 format music Automatic power-off memory function Cigarette lighter power: DC12V-24V voltage power supply; Bluetooth version 4.1 FM transmitter frequency: 87.5-108MHZ Size: 8 x 4.8cm Instructions for use: Download your favorite MP3 songs to the memory card u disk and insert the car MP3 port. Insert the car MP3 transmitter into the 12V car cigarette lighter port; Adjust the frequency of the car radio to the same frequency as the car MP3 transmitter display; The two channels are consistent, the car transmitter automatically plays music files and converts the music signals into FM signals, which are accepted and played by the car FM system. Package List: 1 x Car Music Player Transmitter