AT&T TL88002 Accessory Cordless Handset, Silver/Black | Requires an AT&T TL88102 Expandable Phone System to Operate DECT 6.0 Technology Accessory Handset Only requires the TL88102 to Operate 2-Line Operation Caller ID/Call Waiting  stores 50 calls Handset Speakerphone DSL Subscribers may need to us a DSL Filter For optimal performance batteries should be charged for 16 hours prior to use