Motorola MD451 2.4 GHz Digital Expandable Cordless Phone with Caller ID (Silver) 2.4 GHz digital signal; expandable to 4 handsets Caller ID with visual call waiting, 50 name-and-number memory Handset speakerphone, 3-way conferencing Headset compatible, intercom, walkie-talkie function Illuminated keypad, 4-line LCD, desk or wall mounting