Advanced microcomputer technology and automatic human sensitivity are applied to saluting guest/alarming doorbellExtra ordinary performance energy-saving and easy to useSpecial sound device and anti-interference tech make it effectively detect the movement of the human in the detecting area of all environments such as apartments, hotels, factories, hospitalsIt does not only bring convenience but also bring happiness and security senseSpecifications:Effective detecting distance: 5 to 10 metersEffective angle: 110 degreesAlarming sound: 85 to 100dBIt is suitable for dwelling house, tier buildings, multipleSay dingdong or dingdong, hello welcome that can be set when a visitor comesUse AA 1.5V battery-operated
