Microsoft LifeChat LX-6000 50 Pack. Device connectivity: Wired, Device interface: USB. Ear coupling: supraaural, Acoustic system: closed, Headphone frequency: 75 - 20000 Hz. Microphone frequency: 50 - 20000 Hz, Microphone sensitivity: -43 dB. Dimensions (WxDxH): 156 x 60 x 175.5 mm, Weight: 141.6 g. Operating temperature range (T-T): 0 - 40 °C, Storage temperature range (T-T): -20 - 60 °C