[ DESIGN] - Crystal not easy to fade, sensitive . Clearly shows caller ID that office and home use is more convenient. [CONVENIENT STORAGE] - 30 group call number storage inquiry, you can long press the call-in to quickly check the information. Built-in 5 group call number and call time query. [VOLUME CONTROL] - Two optional volume buttons on the side for easy control. More intimate user experience. [/ANTI-JAMMING FUNCTION] - Ensures efficient and safer use. [/DTMF STANDARD CALLER ID] - Never miss important information. Supports callback function and one-key .