... bluetooth function 2.Built-in rechargeable lithium battery 3.TTS system book function DESCRIPTION: 1,Rearview mirror display and bluetooth ... Suppression/DSP Technology 4,Built-in Speaker&Microphone/FM Transmitter/Wireless Earphone piece 5,Supports U-disk and SD/MMC ... ,TTS system book function 7,Built-in rechargeable lithium battery 8 ,Can connect parking sensor,and show the distance on the LCD display ...