*Driver Unit: 2pcs dia. 40mm *Frequency Response: 20-20kHz *Impedance: 32ohm *Sensitivity: 110dB *Plug: USB 2.0 *Characteristic Build-in Sound Chip Latest USB technology: Uses the latest USB circuitry to give a very low internal noise and a high signal-to-noise ratio; No auxiliary power or sound card required. Full-duplex capability: Full-duplex (microphone as well as speaker) USB adapter for the ultimate in both input and output performance. Plug-and-play convenience: Plugs right into your USB port Uses standard Windows drivers: Works with Windows 98SE, ME, 2000, XP, and Vista operating systems; No additional software required!