Feature: Play music from USB (Universal Serial Bus) disk & TF card The inside of the mobile phone via bluetooth audio & higt quality music to car audio I go with the call voice number, voice prompt function The launch of FM 99.9 M Hz, frequency:87.9 M Hz, 103.0 M Hz, 107.9 M Hz Answering key independent, independent of the hang up button The bluetooth hands-free function, with DSP For echo cancellation function Specification: Rated operating voltage: 12/24 V Consumption rate of: 0.5 W Operating temperature: -10~70 degree Frequency response: 20 Hz-15 Khz Audio format: MP3 Version: V3.0+EDRbluetooth transmission distance: 10~15MFM emission frequency: 87.9 M Hz, 99.9 M Hz, 103.0 M Hz, 107.9 M Hz Package Included:1 X FM Transmitter 1 X User Manual