ZNU AUDIO Radio/WMA/MP3/USB/SD AUX In Dash Car MP3 Player AM/FM Receiver Stereo System Head Unit Functionality: Car Radio, MP3 Player,SD,USB connection Support USB/SD interface ,Support MP3 fomat Rated output power:12V4W,Maximum output power:12V5W 2channels Frequency range:87.5MHz-108MHz MP3 Player:Frequency response:100Hz-10KHz(5dB);SNR:45dB;Channel isolation:30dB;Harmonic distortion (at 1 kHz):5%;Stereo channel balance:3dB