USB Car Bluetooth MP3 Speakerphone is a combo gadget. It is a MP3 Player but also Bluetooth wireless speakerphone. It has a built-in rechargeable battery and microSD memory card slot which can read SD(HC) memory card and play MP3/WMA audio files directly. With the wireless audio technology - A2DP, you can enjoy Excellent High Quality Stereo Music. It also works like a hands-free speakerphone.You can connect it to a Bluetooth-enbabled PC or mobile. When a call comes in, just simply tell the computer to answer the call, and then you can chat with your friends through this hands-free device.