... playback music file after plugging in the MP3 player, Flash driver, SD/MMC card USB MP3 SpeakerFeatures:Electrical parameters Equalizer: BASS,CLASSIC,ROCK ... 800ma min 20ma Harmonic distortion: +/- 2% Power supply : 1) by USB cable or DC cable 2) by AC adaptor (5V, 1A ... format:MP3, lay 1-3 External input:one USB port with HOST function/external MMC/SD slot/one LINE-IN port USB mp3 speaker ...