... usb mini speaker 1,USB mini speaker for laptop, mp3 and mobile phone 2,support USB and SD card 3,built-in rechargeble battery Futures:*USB Mini ... mp3 and mobile phone *Support USB and SD card*Stereo sound design, limited space to enjoy unlimited high-fidelity music* ... Voltage: USB,DC 5V/750mAh*Distortion: ≤0.3 %( 1W 1KHZ)*Separation:≥80dB*S/N Rate: ≥83dB*Accessories: USB cable, audio cable, battery