The Polycom Soundstation 2 Conference phone Non Expandable enables users to speak in a normal voice and be heard clearly up to ten feet away from the unit. This next generation conference phone offers industry-leading full duplex for natural, simultaneous, two way conversation and is ideal for small to medium conference rooms. The sound quality is equal to the SoundStation Premier and has a 50% increase in microphone sensitivity over the award winning SoundStation. This phone is compatible with: Polycom Soundstation 2 PSU, Polycom Soundstation 2 Mic Pods, Polycom Soundstation 2 Exp, Polycom Soundstation VTX1000.