1.[Bluetooth to Aux Adapter]Bluetooth 5.1 Receiver to 3.5mm Auxiliary adapter for car stereo, speaker, amplifier, headphone, or any other audio device. Many cars such as older Toyota don't have bluetooth function, but you want to enjoy music and make phone call, this bluetooth adapter will be your perfect choice. 2.[Bluetooth Name YP04]YP04 is the Bluetooth name.It's easy to use,Firstly Plug 3.5mm audio bluetooth dongle into 3.5 aux jack, Then Connect the USB port to USB power source like Power Bank,Vehicle USB slot,DC USB A adapter,USB Hub on Laptop,the green light flashes quickly.Then search Bluetooth name'YP04' and connect it,the green light flashes slowly when connected. play music on the phone rhythm will come out from the car speaker/headphone. 3.[Hi-Fi Stereo Sound Quality]Built-in Bluetooth 5.1 Chipset,it is clear sound for both listening and speaking.Built-in microphone, allows you to enjoy phone calls with hands- calling straight through the car's speakers. With this Bluetooth car aux receiver you will be more and convenient to listen to music,make phone calls,use GPS navigation when driving. 4.[1-to-2 Dual Connection]This car Bluetooth to 3.5mm AUX adapter has 1-to-2 feature that allows you to connect two phones at the same time, making it easier to share music and switch between two devices. It also has an automatic reconnection function, ensuring that it automatically connects to your phone again when you to your car.