AT&T SL80108 DECT 6.0 Digital Cordless Expansion Handset (Titanium and Carbonite) DECT 6.0 Digital technology for increased clarity and range Caller ID/Call waiting compatible "THIS PHONE DOES NOT WORK INDEPENDENTLY. IT WILL ONLY FUNCTION WITH THE FOLLOWING AT&T BASE UNITS: AT&T Model SL82318 AT&T Model SL82218 AT&T Model SL82418 Please check your phone base model for the amount of handsets that can be added" Conference call between an outside line and up to 2 handsets 1-year limited warranty