VTech i5803 Accessory Cordless Handset, Black/Silver | Requires a VTech i5800 Series Expandable Phone System to Operate 5.8 GHz digital spread spectrum signal For use with i5853, i5857, i5866, and i5867 expandable systems Caller ID/call waiting, 50-call memory 50-number phone directory; distinctive ring detection Multiple ringers plus custom-recordable ring tones