Model sp u200 Suppot os windows@2000/xp(all use windows built-in audio driver) Coverage hand free coverage range about 1 meter Built-in microphone sensitivity -44db+/-3db Frequency roponse 20-16khz Built-in speaker frequency range 120~20khz Built-in speaker impedance 4ohm, +/-15% Built-in amplifier output power 2w Ajustment receiver volume adjustments Echo cancellation up to 45db Noise suppression superior noise suppression up to 15db Automatic calibration support automatic calibration when power on Full duplex support full duplex Power 5v, 500ma max Weight 185g Regulation&standard fcc / ce