CS520 Over-the-head binaural headset. Hands-free productivity. Outstanding audio quality. Conference with up to three additional headsets. Power-saving features. Talk time: up to 9 hours. Headset weight: 94g. Wireless frequency: DECT 6.0. Range: Up to 120 metres. Audio Performance: Narrowband or wideband; up to 6, 800 Hz. Hearing protection: Sound Guard DIGITAL protects against sound levels above 118 d BA; Anti-startle detects & eliminates any large sudden increases in signal level; Time-Weighted Average prevents against noise level from exceeding 85 d BA.