The VTech CS5319 DECT 6.0 Expandable Cordless Phone with Caller ID and Handset Speakerphone is built to give you all the features a busy household needs. A full-duplex handset speakerphone allows both ends to speak and be heard at the same time for conversations that are more true to life. Caller ID entries display on a large, backlit LCD screen so you can see who?s on the line even in the dark. Easily block up to 150 names and numbers with the Call Block. DECT 6.0 transmission gives you private, interference-free sound from any room in your home. Easily add accessory handsets?up to 5 total? with just one phone jack