1.This equipment can detect battery's voltage. 2.Support Bluetooth hands-free phone calling via its build-in microphone. 3.Support mobile's A2DP fuction. Musicwill be played directly while the mobile phone is connected. 4.Mobile phone can be connected automatically when the device powered on. 5.Support an external TF card/U disk, can play music files in MP3 format. 6.Integrated car charger of output 5V-2000mA,is available.