Designed for busy households, the sleek, 4-handset KX-TGF344B not only makes everyday call management easier, a dedicated Call Block button makes it one-touch simple to register up to 250 unwanted numbers—even during ringing and talking. Expandable to 6 handsets, the system includes a baby monitor to alert you when the baby wakes up, plus a bright 2.5-inch LCD for maximum readability, 100 number phonebook, 17 minutes of voice messaging, noise reduction, power backup and key detector compatibility.