https://www.theguardian.com/technology/2021/sep/20/ring-video-doorbell-4-review-pre-roll-is-a-battery-bell-gamechanger

Simple to install and use, Amazon’s smart doorbell now has a much better view of events at your door

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.