Ring device on my network
Ring is the Amazon-owned home security brand known for video doorbells.
What Ring makes
Ring makes video doorbells, indoor and outdoor security cameras, floodlight and spotlight cameras, Chime units and the Ring Alarm base station.
What the device on your network probably is
Most likely a Ring video doorbell or security camera. Next most likely a Ring Chime or Alarm base station.
How to work out which device it is
In the Ring app, open each device's Device Health page to see its network details. Chimes and base stations are listed there too. Unplugging or removing the battery from a unit makes its entry disappear.
Should you be worried
Ring devices are mostly cameras and doorbells. Expected if you installed one; in a rental or shared building, ask who owns it and where it is.
The app finds every device on the Wi-Fi you are on, at home or in a rental, and puts the vendor next to the hostname, the services it advertises and its open ports, which together usually name the product. Where it cannot tell, it says so instead of guessing. Get RECON for iPhone — one-time purchase, no account, nothing leaves the device.