Bengoo Wireless FM Transmitter With Bluetooth Headset Multifunctional Handsfree Car Kit Modulator Radio Adapter with 3.5mm Aux IN/Univeral LCD/Hands-Free Calling/Music Control/Mic and Charging Port This is a Bluetooth hands free car Kit with detachable earphone, can hands free Talk or take private conversation by earphone, also can transmit music stored in Cell phones to car FM stereo system Dual USB output 5V/2.1a,works as car charger for other devices when function. (The LED display will Show the current automatically) If your MP3 Player or MP4 don't have Bluetooth function, don't worry, this car Bluetooth transmitter is also compatible with 3.5mm aux in Jack! Voice Prompts incoming call number and operation State,100% unleash your hands from the Cell phones. LED display: Show the car battery voltage when drive your car with this car Radio adapter connected. That make you keep your car work in a safe condition.