AT&T CLP99006 Accessory Cordless Handset, Silver | Requires AT&T CLP99286, CLP99386, CLP99456, CLP99486, CLP99546, CLP99556, or CLP99586 to Operate Compatible with AT&T base models CLP99286 / CLP99386 / CLP99456 / CLP99486 / CLP99546 / CLP99556 / CLP99586 Download up to 6,000 cellular phonebook entries onto the cordless handsets. Connect up to two cellular lines and one landline to your cordless system. Then, enjoy the Freedom to make and receive calls on all three lines-all at once. Handset displays the Name, number, time, and date of incoming calls. Enjoy a speakerphone that can keep up with your calls. Increase participation by allowing both ends to speak-and be heard-at the same time for conversations that are more true to life. Adjust the volume up or down to best suit your needs.