4-inch multi-touch screen with 480x800 resolution Optimal HD audio, full duplex technology Yealink Noise Proof Technology Built-in rechargeable lithium battery Up to 20 hours talk time (in ideal conditions) Up to 75 hours standby time in Wi-Fi mode (in ideal conditions) 20-foot (6-meter) and 360° voice pickup Built-in 6-microphone array for voice pickup 5-way conference call Hybrid UC meeting