The wireless Baby Cry Transmitter is a small unit that immediately alerts you when your baby starts crying by sending a signal to a Sonic Alert receiver. At least one Sonic Alert remote receiver needs to be used with the BC400 transmitter. A sensitivity knob lets you adjust how sensitive the transmitter should be to detect your baby's cries- depending on where you place the unit. The BC400 does not have any cords - simply plug it into a wall outlet - so you can place it near your baby without them grabbing on wires. FeaturesAdjustable sensitivity control can be set to alert you to sounds as soft as a baby's whisperPlugs into any electrical outlet in the baby's roomNo lamp flashes in the baby's roomBuilt-in indicator light shows you that it is workingNo built-in outlet to plug in a lampItem Weight - 1 lbs.