Dual USB Car Charger: 2 USB charging ports can charge most USB devices. 3. With USB reading and charging function; Smart 1 charging port, can intelligently identify Android or iOS devices and charge. More Compatibility: Wireless Bluetooth FM Transmitter Adapter for Car Radio, Streaming Calls/MP3 Music/Phone Voice to Car Speakers. Compatible with iPad, iPhone, Samsung, Google, LG, HTC and Bluetooth devices. Hands-free Function: Built-in microphone, automatically switch from music playing state to hands-free mode when answering a call. One-touch answer/reject/interleave/recall. Car Battery Voltage Function Displays voltage for 3 seconds when plugged into the car socket port. Always keep the battery healthy. Then it will turn into auto play mode. Music Playback: Support Bluetooth/U disk/TF card/MP3/wma player. Adopt anti-interference performance and CVC technology. Listen to music while charging. Automatically connect to memory pairing when powered on.