VTech 5820 Accessory Cordless Handset, Gray | Requires a VTech 5831 or 5881 Expandable Phone System to Operate Accessory handset for VTech VT-5831 and VT-5881 expandable cordless phone systems 5.8 GHz digital spread spectrum technology Caller ID with call waiting Handset speakerphone 3-line backlit LDC; wall mountable