Plantronics S12 Corded Telephone Headset System 64703-03 2-in-1 Convertible Headset For Over-the-head Stability Or Over-the-ear Convenience Noise-canceling Microphone For Clarity In-use Indicator Light Lets Others Know Phone Is In Use Hands-free Convenience &amp; Comfort Over-the-head and over-the-ear configurations Volume and mute controls Noise-canceling microphone, call clarity technology Convenient headset stand Compatible with single and multi-line phones