Siemens 2415 Gigaset 2.4 GHz Cordless Phone System with Caller ID and Answering Device (Gray) 2.4 GHz digital spread spectrum operation (base and handset) Built-in digital answering machine, 22-minute memory Caller ID/call waiting with 50-call history; 120-entry call directory Expandable to 4 handsets Volume and ringer tone control