Elecom GHS 20. Device connectivity: Wired, Device interface: USB, Cable length: 2.5 m. Acoustic system: closed, Headphone frequency: 20 - 20000 Hz, Impedance: 64 Ом. Microphone frequency: 100 - 10000 Hz, Microphone sensitivity: 58 dB. Weight: 0.36 kg. Compatible operating systems: Windows XP/Vista/7