Bluetooth Car Kit, Jupi-storm Bluetooth CSR 4.0 Wireless Stereo Music Receiver/HandsFree Car Kit with Knob Rotatable Adjustment Built-in Mic/3.5mm Output, Siri/Voice Activation, Updated Blue LED Ring Features:It can connect your cellphone with car audio system through Bluetooth;Built-in microphone,You can play music wireless and receive calls with your hands free;Human-centreed design and simple operation. Rotatable Adjustment:No other button to control volume or songs.You just need to rotate the product and control everything.You can simply rotate the knob left or right to go to the previous / next song, or rotate & hold the controller a few seconds to decrease or increase the volume. Latest Bluetooth 4.0 technology : Full-speed transmission and low power consumption. Up to 10 metres range. Supports pairing two smarts devices at once. You will never miss a call again with this Bluetooth car kit. High quality sound: Built-in microphone transmits your voice to your phone. Echo and noise cancellation ensure you non-stop wireless stereo music and clear phone calls. Some cars may have the noises caused by Ground Loop ,you will enjoy good quality audio when use with Jupi-storm Ground Loop Noise Isolator,it can completely eliminate noise and hum, No more noise and static! Auto connection: Automatically power on and connect to the last paired device when starting the car. Pair two Bluetooth devices at once! Play music and answer calls from two separate devices without disconnecting and repairing.