Product characteristics1. The device can detect battery voltage;2. Support Bluetooth headset to respond, high-definition call;3. Support Bluetooth hands-free calls, built-in microphone, secure answer the phone;4. Support A2DP cell phone function, connect directly by Bluetooth and play high quality mobile music;5. Mobile phone can be connected automatically when the device is on;6. Support USB flash drive to play MP3 / WMA music format files;7. Car charger, 5V / 3.1A output, you can charge for portable devices.headset 8. Bluetooth charging function, use while charging9. Power switch Independent, ready to turn off the power, not the car battery loss Product Parameters1. Bluetooth Version: V4.2 2. Voltage Limit: 9-26 V 3. Rated operating voltage: 12 V-24 V 4. Sensitivity: -42db +/- 3 db 5. Working Current: 45mA (max) 6. Standby Current: 25mA (max) 7. Frequency: 2.402-2.480 ghz 8. Bluetooth Effective Range: 10 meters 9. Sensitivity: -92 dBm 10. RF Output: 4 dBm 11. FM Frequency: 87.5 MHz-108.0 MHz Power 12. Transmitted: 87 dBuv / 107 dBuv 13. Microphone Effective Range: 2 meters