Phone Only Model, Not for Computer. Included Electronic Hook Switches (EHS for Remote Answering Feature) allows you to Answer and Hang-on a call remotely within the wireless 300 feet (Max. May be reduced by your environment) headset range.Even if you are far from the Desk Phone, when an incoming call, you hear melodies in your ear cordless headset, and you can answer the call if you press the call button on the ear headset.Compatible with Polycom Phones Soundpoint ip335, ip430, ip450, ip550, ip560, ip650, ip670, vvx300, vvx310, vvx350, vvx400, vvx410 Note : Handset Lifter Wireless headset like CS540 with HL10 is hard to install on the Phone due to the Phone Handset Shape.* Improve Productivity as you're able to gather information throughout your office while continuing to talk.* Noise Cancelling Microphone filters out background noise * Digital Signal Processing/DSP makes Outstanding Sound Quality and also eliminates Wi Fi interference and Acoustic protection to protect Ears. * Incoming call notification and One-touch call answer/end button, volume control with mute, manage calls within wireless range from the charging base * Max 10 Hours Talk Time (It will be reduced when operating in high speaker volume or Calls at a long distance, in a state such as a radio wave blocking environment).