Digital transmission with zero interference, excellent sound quality and microphone sensitivity Extra long transmit range up to 800 m (open area) Low Radiation (Max 20mW) insured by special features such as voice activation, (Zero radiation) function, automatic power reduction system (APRS) and (Zero radiation) function Xtra Large Rechargeable Lithium Batteries (1300 mAh) and docking station to both units Multiple baby units (up to 3) can connect to one parent unit. Talk back function, vibration on parent unit and night light on baby unit