Description:1. Built-in-Li-ion Battery.2. Support TTS function.3. Support dual standby.4. Support MIC mute function.5. Connect automatically when power is on.6. USB port for software update and charge.7. Answer/end/reject a call, last call redialing,and call switch.8. DSP technology, Full duplex, CVC noise and echo suppression.9. Support A2DP function, can play cell phone music and control it completely via Bluetooth car kit.10. Fixed on the steering wheel with special hook structure which is convenient for fixing and operation.