Full frequency FM transmitter. Digital Display. Supports Line audio input. With power off switch (USB direct connect). Supports u disk tf card player. Supports mp3, WMA format music, wireless answer, hang up reject, redial calls and other functions. Wireless stereo music play, support USB output voltage, the maximum output 5v/2.0A. Automatic power-off memory function. 1. Power on the device and has voice prompts: Bluetooth is ready to pair.2.Turn on cellphone or other Bluetooth device and search JKS.ZSY-RGB in Bluetooth column.3.There is a voice prompts after connected. Bluetooth connected successfully.4. Bluetooth Version 4.0, Can connect with Bluetooth version 4.0 or below version. The FM transmitter will display BT with the voice prompt, “Bluetooth is ready to pair” and the display with alternate from BT to frequency until you connect with Bluetooth or insert the USB.5. Good Quality and More Compatibility. 2.1A and 1.0A,Input 5v offer convenient and charging for you and your friends.USB charging cable is not included. Built-in Microphone,Switch to Hands-free mode automatically from music playing status when receiving calls.Answer/Reject/Hand up/Recall all in one keypad. Show 3 seconds of Auto voltage when put in the Car cigarette lighter and Speech battery case.Let you always keep battery state of health.Then it will enter the automatic play mode. Support Bluetooth Music/ USB Disk/ TF Card / WMA / MP3 format. Listening to music while charging.Power off memory function,From broken song began to play. Bluetooth transmitter ,Transfer Calling / Music / FM / . 5% every hour low power consumption when use bluetooth play music. Mobile navigation,Voice broadcast . Bluetooth connect distances : 5 meters. Fit for most of android and IOS.