Built-in Bluetooth Hands-free and Audio Streaming CX501's built-in wireless Bluetooth interface supports HSP/HFP for hands-free operation and PBAP for phonebook download. You can easily communicate with the outside world by listening to phone calls through the car's audio system and talking through the embedded microphone. And with A2DP/AVRCP support, you can enjoy music streamed from your mobile phone. Large Rotary Volume Control for Comfortable Operation This large volume control knob, combined with the ergonomically symmetrical design of the unit, helps to provide equally comfortable operation from the driver side or passenger side. Using it is so intuitive and natural, it minimizes stress for the operator and contributes to driving safety.