TONOR USB External 7.1 Channel 3D Virtual Audio Sound Card Adapter This sound card adapter can drive all kinds of high resistance earphone, headset and stereo with its high power. The SNR rate is up to 90dB. No drivers required for Window2000/Window XP/Window2003 system, just plug&play. Compatible with USB 2.0 digital audio output, virtual 7.1 sound channel processing power. 16 tempo preset modes and 23 sound field preset modes. The USB Virtual 7.1 Channel Sound Adapter is a highly flexible audio interface which can be used either with Desktop or Notebook systems, It turns your stereo speaker or earphones into 7.1 channel environment. No drivers required,just plug and play for instant audio playback,also compatible with all major operaiton systems.