The latest iteration of Amazon's battery-powered Ring doorbell adds a new feature to capture the early details of events most competitors would miss without needing to be plugged in. It tops Ring's battery-powered range, which starts at £89. The look and basic function of the Doorbell 4 is very similar to Ring's older models. It has a camera with night vision, motion sensors and a large doorbell button. When someone pushes the button Ring's signature chime plays and an alert is sent to your phone. You can view a live feed and speak through the doorbell using the app from anywhere with internet.