1. Use microwave radar to detect the alarm, it trigger the alarm as long as someone is standing at the door. 2. 1080P HD video doorbell camera with 4.3 inch display. 4. Stay alarm notification, when someone stays at the door, the camera capture and record video at the same time, which can be viewed in playback (memory card required). 3. Built-in 5000mAh rechargeable battery and 5V 1A USB cable power supply, with low battery alarm function. 5. One-way intercom, can only hear the visitor's voice, can not communicate with the visitor., Weight: 0.98987555638 pounds, Manufacturer: ximie