1)Support MP3/WAV/CDA format 2)Direct USB plug 3) LED indication 4) Frequency response: 20Hz-20KHz 5) Distortion: <0.1% 6) Signal/noise rate: 90dB 7) Interface: USB 8) Power source: 1 x AAA size 1.5V battery 9) OS support: no drivers needed for Windows 2000/ME/XP 10) Driver needed for windows 98/98SE 11) Output power: 5mW+5mW 12) Dimensions: 88 x 26 x 17mm