Core Features: Yealink Acoustic Shield Technology Optima Audio Experience Touch Screen Lcd: 4.0 Inch 480 X 800 Capacitive Touch Screen Multiple Devices Connection Speakerphone Mode Crystal Speakerphone Builtin Usb Hub: 2Ports Usb 3.0 Hubqi Wireless Charger / Wireless Mobile Phone Charger Customizable Busy Light / Supports Busy Light Uc Certified