Microsoft LifeChat LX-4000. Device connectivity: Wired, Device interface: USB, Cable length: 2.1 m. Ear coupling: supraaural, Headphone frequency: 75 - 20000 Hz, Impedance: 32 Ом. Microphone frequency: 50 - 20000 Hz, Microphone sensitivity: -43 dB. Dimensions (WxDxH): 156 x 175.5 x 60 mm, Weight: 120 g. Operating temperature range (T-T): 0 - 40 °C, Storage temperature range (T-T): -20 - 60 °C