Plantronics CS510 Wireless Headset System [84691-01] Over-the-Head Monaural headset is the over-the-head wireless headset to replace the CS351N and features the lightest DECT headset on the market. Go mobile and multi-task up to 350 feet from your desk with answer 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