A 2 in 1 monitor bringing together the use of the sensor pad and digital coding to give you constant piece of mind. The Angelcare Digital Monitor works on a digital code system to aid in the elimination of interference. Baby Unit: Soft blue glow nightlight with on/off option 3 channel option Nursery Room Temperature Display Alarm and low battery indicator Adjustable sensitivity switch Alternatively can be used with 4 AAA batteries. Parent Unit: Volume Control Switch 3 channel option Voice Activated In Range Indicator Alternatively can be used with 3 AAA rechargeable batteries. Parent Unit has a range of up to 120 meters 394 feet There are 4 function options for how you want to monitor your baby from your parent unit: Movement: This option will only transmit movement from the baby, not sound. Sound/movement/tic: To hear sounds, see sound lights and hear a 'tic' sound with every movement baby makes. Sound/movement: To hear sounds, see sound lights function but without the 'tic' sound. Sound: To hear sounds and see sounds lights on parents units.