... speaker Applicable to USB,SD/MMC card,computer,mp3,mp4,mobile,ipod,iphone Built-in lithium battery,recharge Digital MINI ... card small speakers-Stereo sound,ultra-low sound powered from the phone.-Support USB,SD card ... .You can use rechargeable or external power adapter USB charging voltage of 5 volts.-Alloy,bass vigorous ... -20KH2>85dB1-2 hours4-5hours wireless USB laptop speaker