Wireless Bluetooth FM Transmitter Car Kit Radio Receiver with 5V/2.1A USB Charger output Support USB Flash Driver and Micro SD Card AUX output and input Play music from USB disk and TF Card, TF Card reader Audio/music playback via Bluetooth A2DP Support Bluetooth HFP/HSP,A2DP/AVRCP Profiles Bluetooth Hands-free function: Full Duplex, DSP(Digital Signal Processing) Technology, CVC technology for echo cancellation and noise suppression Charge for iPhone/iPad/Samsung/Htc. Power switch Wide power supply suitable for variety of cars. Using FM Transmitter function: 1. Plug the FM transmitter into your vehicle\'s cigarette lighter or power port. Tune your radio to an unused FM frequency, then match the same frequency of this unit. 2. Insert a USB flash drive or SD card which containing MP3 files into USB port or memory card slot of this unit accordingly. It will play and transmit the MP3 files automatically. 3. Line-in function: Use the provided audio cable to connect an MP3/MP4 players or another external device to the AUX input of this unit.