4-Line DECT 6.0 Accessory Handset is designed for use with RCA expandable 4-Line Corded Telephone Systems. Handset has speakerphone, volume control, Call Waiting/Caller ID, 99 name/number Caller ID history, 94 record programmable name/number directory, Do Not Disturb feature, and mute. Trilingual display can be viewed in English, Spanish and French. Includes headset jack. Hearing aid compatible. Headset does not operate independently.