The MAXAttach expands by connecting additional phones, not just expansion microphones. This creates a better distribution of loudspeakers and microphones so all participants can hear and be heard clearly. It also provides easy access to user controls such as volume and mute. All connected phones share control. Volume and mute changes on one phone will affect all phones. PRODUCT FEATURES INCLUDE: Improves audio quality by eliminating echo Noise cancellation: Removes background noises from fans or HVAC systems making speech audio easier to understand Full-duplex sound: Allows participants on both ends of the call to engage in highly interactive, productive conversations First-mic priority : Eliminates hollow tunnel soundby activating only the microphone closest to the person speaking Three microphones: Provide 360€ audio pickup to ensure participants are heard clearly at the far-end of the call Speed dial : Stores 10 frequently dialed numbers.