Nulaxy FM Transmitter Bluetooth Modulator Handsfree Car MP3 Player Support USB KM21 FM Transmitter Bluetooth FM Modulator Handsfree Car MP3 Player Support USB Flash Drive SD Card With USB Charger Aux Out/In Bluetooth Version: V3.0 + EDREffective Bluetooth Range: 10 metersFM Frequency: 87.5MHz - 108.0MHZWorking Voltage: 10V~24VAudio Input/Output: 3.5mm audio interfaceUSB Charging Port: 5V/2.1A Featuer Multi-Playing ModesA: Via Bluetooth; B: Via Micro SD/TF card (MP3, WMA, WAV format supported); C: Via USB flash disk; D: Aux input and output Via 3.5mm Audio cable (MP3 player,tablet, etc.),Short press the Mode button to switch the playing modes Crystal Sound and Hands-free Calls Built-in microphone feature can offers your hands free talking and wonderful music, utilized most advanced interference and noise cancellation technology, to grant most crystal sound quality. 1.44'' Large LCD Backlight Display Screen: 1.44 inches screen provides clear display: song name, incoming phone number and voltage of the car battery. Faster Charging STATION: Comes with a 5V-2.1A charging port which can charge most USB devices, better charging performance! Three Song Playing Modes and Reading TF/USB Disk folders It can read folders in TF Card or USB disk ,also supports Normal,Repeat and Shuffle Playing Modes while playing songs in USB flash driver or TF card ,just long press the Mode button . Power on/off Manually Long Press 5 seconds phone button to turn on or turn off, humanity operation and easy operate. Package Included:1* FM Transmitter1* 3.5mm Audio Cable1* User Manual User Tips All functions keys are designed for Bluetooth Mode,if you connect through Aux-in using audio cable , you will have to operate on your phone to adjust volume ,change songs or answer phone callsPlease check if both the car radio and transmitter are on the SAME station. If not, please set both of them on the same station to avoid noise .To achieve best audio quality, please set the volume on your phone to maximum and then adjust the volume for your car stereo; you are not suggested to adjust volume of your car speaker to maximum (this will bring lot noise).If there is no sound when you make a phone call, you can try to turn up the voice call volume on your cell phone and volume of the transmitter.Please only use Micro SD card in FAT format up to 32G memory ; it only supports music in MP3 WMA and WMV formats Feel free to contact us for any questions !