Plantronics W440 Savi Office Wireless PC Headset -Convertible Headset with multiple wearing options (over the head, over the ear, and behind the neck, Noise canceling microphone helps to block out your surrounding noise, Hot swappable battery - lets you change battery in the middle of the conversation so you never run out of power (additional batteries sold seperately). Talk time: Battery provides up to 6 hours - Talk time: Battery provides up to 6 hours. DECT 6.0 NA SQL12 technology eliminates interference Wi-Fi network Plantronics