Bluetooth 4.1 Wireless Audio TransmissionYou can enjoy high-quality stereo audio by connecting to Bluetooth-enabled devices, like your smartphone, tablet or PC.Wired And Wireless ModesThe device also works in wired mode by connecting the audio-USB cable. Useful when you run out of power. An empty battery will never stop you now. Built-in MicrophoneThe hidden omni-directional microphone will automatically pick up your voice with remarkable clarity.