This BTFMA Bluetooth FM Transmitter with USB Port for Mobile Devices wirelessly transmits phone calls from your smartphone through your vehicles FM stereo system. It can also be used with non-Bluetooth devices using the included auxiliary cable. You can directly play raw MP3 files by plugging in a SD card or USB drive into the unit. It comes with a convenient remote control to safely switch between radio stations navigate through MP3 files on a USB/SD card go to the next or previous track adjust volume up/down and more. The LCD screen with backlit display permits easy viewing. The unit s flex neck design allows for positioning in multiple viewing angles. A 2.1A USB port allows you to charge your mobile devices while you play music. The unit has 12VDC input and 5V/10 Watt/2.1A output.