... Suitable to fashionable consumers.3.High-efficience professional amplifier.4.USB provides power, mini stereo system.5.Adapt to different ... of device, such as laptop , computer,mp3,mp4,USB disk,SD/MMC memory card,mobile phone. Technique Parameters: Output power: RMS 3W ... battery: 3.7V 500mA Materials: plasticBuilt-in: SD card,USB decoder, Rechargeable li-ion battery Our company provide good quality ...