Features Speaker compatible with iPod , CD player, MP3 player, MP4 player and Mobile; iPod dock / 1/8" (3.5mm) Mini stereo jack Touch volume-control switch USB power supply Stylish design and superb portability Specifications Number of speakers: 2 micro-Titanium drivers housed in a single speaker unit Power Output: 2 x ( 2 to 5)W stereo Input sensitivity: 500mv to 1.5v Respond frequency: 100Hz-20KHz S/N ratio: 85dB Voltage: input 100-250V +/- 15%, AC/12V DC (50 to 60Hz) or DC 6V/1A switch power Battery: 4AA alkaline or nickel hydrogen battery