The Plantronics CS520 wireless binaural headset system provides some of the most powerful, clearest audio at ranges of up to 350 feet thanks to 1.9Ghz wireless technology. Adaptive power systems and noise-canceling microphones make this over-the-ear binaural headset both powerful and versatile, and in-line audio controls and the ability to conference in up to 5 more compatible devices round out the feature set of the Plantronics CS520. Comes with wireless base unit/charging cradle. Adding the optional electronic hookswitch cable or handset lifter, sold separately allows users to answer and end calls while away from their desk. Refurbished units ship with a full 1-year warranty, same as new.