The Philips Avent SCD502 baby monitor allows you to listen to your baby without interference thanks to DECT technology (Digital Enhanced Cordless Telecommunications). This technology gives you crystal clear sound so you can hear baby at all times. Eco mode can be activated to reduce power consumption. Smart Eco mode reduces transmission power for longer battery life. For added safety, the parent unit lets you know when your baby monitor is out of range or needs to be recharged. Don't worry, the parent unit is rechargeable and offers 24-hour battery life. For more mobility, you can also put in batteries. The range is up to 50 meters indoors and 300 meters outdoors.