Plantronics CS520 Wireless Headset System [84692-01) Over-the-Head Binaural headset is the new over-the-head wireless headset to replace the CS361N and features the lightest DECT headset on the market. Go mobile and multi-task up to 350 feet from your desk with answer Noise canceling microphone filters out background noise end and mute controls at your fingertips. And no matter what your preference with three wearing choices there's one to match your personal style. Voice-dedicated DECT (1.9Ghz) technology eliminates Wi-Fi interference and Up to 9 hours talk time on a single charge