It works with any telephone base and perfect for recording those important messages. The unit has full remote operation and voice guided setup and operation . The EM1250 features announcement recording, time / day stamp and call screening. It has a digital counter that works as a message indicator. EM1250 Features: Digital Telephone Answering Device, 40 Minute Record Time, Announcement Record / Check Control, Power On / Battery Low / Message IndicatorLED, Time / Day stamp, Volume Control, System On / Off Control, Call Screening, Big Button, AC Power Connection, Works With Any Telephone"