The Expert Care baby monitor uses digital technology and has many useful features. The Expert Care has a 1000m range and a VOX function: voice-activated to limit waves emission. You will hear all the sounds in the nursery, a series of lights also registers the noise, and the parent unit will start to vibrate. Both the transmitter and receiver can be powered either by the mains, or battery - the parent unit battery is of a quick rechargeable lithium type, the baby unit takes 3 AAA batteries (not supplied). 1000m range. Monitor features: Digital signal. Out of range indicator. 1 parent unit included - portable. Vibrating alert. Night light - to sooth and comfort baby. Power features: Low battery indicator. Parent unit includes mains adaptor - batteries required for parent unit 3 x rechargeable (not included). Baby unit includes mains adaptor - batteries required for baby unit 3 x AAA (not included). General information: Manufacturers lifetime guarantee.