Output power: RMS 4W 2W+2W THD=10% Frequency respond: 150-18000HZ( 3dB) Signal to noise ratio: ! 80dB Power source input: DC 9V/1000mA Function: Metal shell Several ways to supply power for speaker: 1) 4AAA batteries 2) USB power connect line 3) AC/DC power adapter DC9V/1000MA (optional), and when you supply power for speaker by the AC/DC adapter, also you are charging for the Mobile phone synchronously Adjust volume by electron Can link MP3 MP4 notebook CD mobile phone iPod nano Compatible Model: SonyEricsson: W750, W800, W810, 500, 790... NOKIA (optional)