Features:100% Brand new and high quality guaranteed.Dual USB Car Charger : 3.1A and 1A, Input 12v/24v offer convenient charging for you and your friends.BT Function : BT V4.0 ,Transfer Calling / Music / FM / . 5% every hour low power consumption when use BT play music. Mobile navigation, Voice broadcast.Hands Free Function : 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.Music Playing Function : Support BT Music/ USB Disk/ TF Card / WMA / MP3 format. Listening to music while charging. Power off memory function, From broken song began to play.Car Battery Voltage Function : 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.For 12V /24V car, voltage display of car battery under 11.5V /23.1V or higher than 14.9V/27.3V means car battery issue.Please noted the priority play sequence is BT>TF card>USB.Built-in FM transmitter, 87.5-108.0MHz of full frequency.BT connect distances : 5 meters.Fit for Android/IOS.Specification:Condition:100% Brand NewMaterial: ABSColor: As shown in the pictureFM Transmitter Function:The device default channel is FM87.5.Before use, please turn the car radio channel to FM87.5. Then plug the device, it can directly connect car speaker. If there has noise interference, please adjust channels as below:1. Choose an blank and clear channel in the car audio.2. Long press the FM transmitter answer key until the LED display flashing.3. Turning the answer knob adjust the same channel at FM transmitter.4. Short press the answer key to fix the channel.5. Connect phone BT or insert the USB/TF card, FM Transmitter will start to play.Note: Please repeat above steps if has noise interference in the radio.BT Function:1. Power on the device, there is a prompt voice: BT is ready to pair.2. Turn on smart phone BT search the name of .3. After connected, there is a prompt voice BT connected successfully.4. BT function can transfer music from phone to car speakers or answer phone handsfreePackage List:1*Car MP31*Charging Cable1*Instruction Manual