Desk Phone Only models (NOT for Avaya One-X Softphone, NOT for Computer): Compatible with Avaya Desk Phone 1408, 1416, 9504, 9508. For other Avaya Phone models, refer to the HANDSET LIFTER WIRELESS HEADSET ( https://www.amazon.com/dp/B08T3MJYRK ).INCLUDED Remote Answering Switches (EHS) enable you to roam your office while you talk with and Answer incoming calls within reachable MAX 300 FEET cordless range(Max. may be reduced by your environment).EVEN IF you are far from the Avaya Desk Phone, when an incoming call, you hear melodies in your ear-headset, and you can answer the call if you press the call button on the ear headset.* IMPROVE PRODUCTIVITY as you're able to gather information throughout your office while continuing to talk.* NOISE CANCELLING MIC filter 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* CHANGEABLE headset color to Black / Wine color.* MAX 8 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).As an Avaya wireless headset, this best cordless headset for office phone compete with plantroniks cs540, plantroniks cs50, plantroniks savi, jabra pro 920 mono wireless headset.