The VTech UP407 is an Extension Headset, which requires (UP416) Main Console to operate. You can register only one (UP407) Cordless Handset to a (UP416) Console or a (UP406) Deskset. Only one device with the same extension can be used at a time. The ErisBusinessSystem four line operation phone is packed with the best VTech features and manage calls from 1-4 telephone lines simultaneously. The UP407is a full-duplex speakerphone that can keep up with your calls and increase participation by allowing parties on both ends to speak and be heard at the same time. One can store 50 names and numbers and 200 call history. Additional features include 3 languages LCD prompt, One-touch setting, hearing aid-compatible and auto line selection. This is a versatile device designed to expand the capabilities of your communication system. It features a sleek and modern silver and black design, with a large color display and backlit keypad for easy operation. The handset is lightweight and ergonomically designed, making it comfortable to hold for extended periods of time.