product description: 1. Professional-grade car Bluetooth hands-free product 2. Dynamic appearance, fixed directly on the car sun visor 3. Using the latest high-quality CSR company BCS chipset, DSP full-duplex call, CVC Bluetooth erasing and noise cancellation technology 4 support voice dialing call function 5. Last number redial 6. Support Bluetooth mobile phone music playback 7. Answer / hang up / call back / redial / reject function / automatic answer function 8. Built-in high-sensitivity microphone and high-power speaker to ensure the call performance of both parties 9. Built-in large capacity rechargeable lithium-ion battery, long standby time