How does it work?Ring sends users an instant alert when anyone presses its button or triggers its built in motion sensors. The app, which is free, lets you see and talk to who's at your door using 1080p HD video and two way audio. This device also has infrared night vision. Our tester was impressed with its consistent performance: "We didn't see any false positives during our testing," he said. "It diligently recognized every entrance and exit from the door—including those from a dog. " Each kit also includes a free 30 day trial to Ring's cloud video recording platform so you can save, review, and share captured videos.