The Panasonic KX-TGD510B expandable Digital Enhanced Cordless Telecommunications (DECT) 6. 0* Phone System with Call Blocking and 1 cordless handset is a smart, reliable home phone/home office solution designed to make everyday call management easier and more convenient for everyone. Includes one cordless handset in the base unit, expandable up to six handsets (additional handsets sold separately). With a dedicated Call Block button on each handset, it's easy to block telemarketers, robocalls and other bothersome caller numbers. One button registers up to 150 caller numbers - even while the phone is ringing or while you're talking or listening. Quickly see who's calling with 1. 6" high-contrast white backlit LCD handset screens. Soft-touch amber backlit keypads and smartly positioned phone function buttons provide enhanced readability. Assigned pre-programmed ringtones will sound on the phone?s base unit and cordless handsets when corresponding Caller ID numbers are received from incoming telephone calls. With the Panasonic KX-TGD510B cordless phone system you can program and store up to 100 numbers in your phonebook, enjoy the time-saving convenience of nine speed dial settings and handset-to-handset intercom. Guided feature tutorials are available for this cordless phone system on the manufacturer?s website. DISCLAIMER: * DECT 6. 0 is a North American marketing term for DECT devices manufactured for the United States and Canada operating at 1. 9 GHz.