This car transmitter uses an FM radio signal to transmit music and calls from a smartphone to the car stereo Play and transmit music from a TF card using an FM radio signal Transmit music from a smartphone to a car stereo via Bluetooth. Can be used as a hands-free car kit whilst driving. Bluetooth hands-free FM Transmitter and play and transmit the music from TF card to car stereo via FM radio signal. Transmit music from your mobile to the car stereo via Bluetooth can be used as a hands-free car kit during driving via Bluetooth. Comes with MIC, a connected car speaker, and noise-cancelling, and enjoys calls and music while driving.USB CAR CHARGER: Two USB ports allow you to charge two devices simultaneously, one of which can read a USB flash drive. The max current output is 2.1A, providing you with a fast and effective charging experience. Equipped with easy pairing with Bluetooth-enabled stereo audio devices, and hands-free call functions.MUSIC PLAY SYSTEM: 4 choices for music play this Bluetooth FM transmitter can transmit music from a mobile phone, USB flash drive, TF card, tablet, MP3, etc. to a car stereo system via FM signal. You have four choices to play music.VOICE PROMPT: Voice Prompt When it is in pairing mode or Bluetooth is connected, the voice prompt will tell you whether this device is connected successfully or not.HANDS-FREE CALLING: Hands-free Calling With this wireless device, you can conveniently answer/ reject/redial calls through the hands-free function. Noise and wind will be suppressed by CVC technology, creating full duplex sound quality.Specifications:Bluetooth version : V3.0 + EDRFrequency : 2.402-2.480GHzSensitivity : -42b +/- 3db 360Input: DC 12-24VSensitivity: -92 dBmRFOutput: 4 dBmTransmitted Power: 87 dB up / 107 dB upFM Effective Range: 2 MetersVoltage : 5V +/-0.5Effective Range: 5mRF output: 4dBmFM frequency : 87.5-108.0MHzMaterials: ABS and plasticPackage Included:1 x FM Transmitter1 x User Manual