Plantronics CS520 Binaural Wireless Headset System 1-touch call answer/end, volume increase or decrease, mute & flash controls Energy efficient adaptive power system optimizes for range & talk time Conference in up to 3 addition CS500 or Savi headsets for enhanced collaboration New headsets can subscribe to base by simply docking the headset Wireless frequency DECT 6.0, range up to 350 feet, narrow band or wide band up to 6,800 Hertz