1.Clear Sound -Bluetooth V4.1 Car Bluetooth Receiver ,with Noise Isolate technologycan play music and answer phone call with high quality sound^ 2.Auto reconnect and fast pairing : the bluetooth aux adapter paring very fast and can auto Re-connect with most of phone after first time pairing^ 3.No battery Required :USB port for car power source and aux plug for speaker aux Audio port , bluetooth will be on once car running,no need battery and button switch,easy to use^ 4. Dual Link and Built in Microphone :Take calls directly via Bluetooth reciver mic , safe and convient.Small and Thin with Aluminum Housing ,Nice nad simple design, Connections of 2 Bluetooth devices at the same time is very convenient to have fun sharing music.