USB Wired Computer Headset with Microphone Noise-reduction Universal Office Call Center Headphone Support Volume Control Mute Cancelling Suitable for Telephone Operator Computer PC Laptop Gaming Chatting Network Teaching Video Conferencing Model: H630D-USB Color: Black   Speaker Sensitivity: 108±3dB(1KHz at 178mV) Voice coil impedance: 150±15Ω(at 1KHz) Frequency characteristics: 200Hz-6600Hz(at 1KHz) Distortion: ≤5%(1KHz at 178 MV) Appearance size: Φ28mm   Microphone Directivity: all directions Sensitivity: 40±2dB(2.0V, 2.2KΩ, 1KHz) Distortion degree: ≤5%(4.5V, 2.2KΩ, 1KHz) Current consumption: 100~500UA Appearance size: Φ6×2.7mm