The Motorola MBP-140 has DECT technology which makes it 100% interference-free. It has a 50-meter indoor radius, so you'll always hear your little one loud and clear through the parent unit. When the parent and baby unit are disconnected, a beep will sound. The baby unit has a night light, which makes your child fall asleep peacefully. The MBP-140 has volume control which allows you to turn the volume of the parent unit up or down. This comes in handy if the parent unit is placed a little farther away.