Yealink Optima HD IP Conference Optima HD voice, Full duplex technology, 20-feet and 360 degree voice pickup, Two wireless microphones (optional), Built in 3-microphone array, Android 5.1 OS, 5-inch multi-touch screen with 1280*720 resolution, Power over Ethernet, 5-way voice conferencing, Built-in Wi-FiBluetooth, Connect to PC via micro USB, Support call recording.